Littérature scientifique sur le sujet « 3’ terminal exon »
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Articles de revues sur le sujet "3’ terminal exon"
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Davis, Mary Beth, Jon Dietz, David M. Standiford et Charles P. Emerson. « Transposable Element Insertions Respecify Alternative Exon Splicing in Three Drosophila Myosin Heavy Chain Mutants ». Genetics 150, no 3 (1 novembre 1998) : 1105–14. http://dx.doi.org/10.1093/genetics/150.3.1105.
Texte intégralRésumé :
Abstract Insertions of transposable elements into the myosin heavy chain (Mhc) locus disrupt the regulation of alternative pre-mRNA splicing for multi-alternative exons in the Mhc2, Mhc3, and Mhc4 mutants in Drosophila. Sequence and expression analyses show that each inserted element introduces a strong polyadenylation signal that defines novel terminal exons, which are then differentially recognized by the alternative splicing apparatus. Mhc2 and Mhc4 have insertion elements located within intron 7c and exon 9a, respectively, and each expresses a single truncated transcript that contains an aberrant terminal exon defined by the poly(A) signal of the inserted element and the 3′ acceptor of the upstream common exon. In Mhc3, a poly(A) signal inserted into Mhc intron 7d defines terminal exons using either the upstream 3′ acceptor of common exon 6 or the 7d acceptor, leading to the expression of 4.1- and 1.7-kb transcripts, respectively. Acceptor selection is regulated in Mhc3 transcripts, where the 3′ acceptor of common Mhc exon 6 is preferentially selected in larvae, whereas the alternative exon 7d acceptor is favored in adults. These results reflect the adult-specific use of exon 7d and suggest that the normal exon 7 alternative splicing mechanism continues to influence the selection of exon 7d in Mhc3 transcripts. Overall, transposable element-induced disruptions in alternative processing demonstrate a role for the nonconsensus 3′ acceptors in Mhc exons 7 and 9 alternative splicing regulation.
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Lou, Hua, Karla M. Neugebauer, Robert F. Gagel et Susan M. Berget. « Regulation of Alternative Polyadenylation by U1 snRNPs and SRp20 ». Molecular and Cellular Biology 18, no 9 (1 septembre 1998) : 4977–85. http://dx.doi.org/10.1128/mcb.18.9.4977.
Texte intégralRésumé :
ABSTRACT Although considerable information is currently available about the factors involved in constitutive vertebrate polyadenylation, the factors and mechanisms involved in facilitating communication between polyadenylation and splicing are largely unknown. Even less is known about the regulation of polyadenylation in genes in which 3′-terminal exons are alternatively recognized. Here we demonstrate that an SR protein, SRp20, affects recognition of an alternative 3′-terminal exon via an effect on the efficiency of binding of a polyadenylation factor to an alternative polyadenylation site. The gene under study codes for the peptides calcitonin and calcitonin gene-related peptide. Its pre-mRNA is alternatively processed by the tissue-specific inclusion or exclusion of an embedded 3′-terminal exon, exon 4, via factors binding to an intronic enhancer element that contains both 3′ and 5′ splice site consensus sequence elements. In cell types that preferentially exclude exon 4, addition of wild-type SRp20 enhances exon 4 inclusion via recognition of the intronic enhancer. In contrast, in cell types that preferentially include exon 4, addition of a mutant form of SRp20 containing the RNA-binding domain but missing the SR domain inhibits exon 4 inclusion. Inhibition is likely at the level of polyadenylation, because the mutant SRp20 inhibits binding of CstF to the exon 4 poly(A) site. This is the first demonstration that an SR protein can influence alternative polyadenylation and suggests that this family of proteins may play a role in recognition of 3′-terminal exons and perhaps in the communication between polyadenylation and splicing.
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Lou, Hua, David M. Helfman, Robert F. Gagel et Susan M. Berget. « Polypyrimidine Tract-Binding Protein Positively Regulates Inclusion of an Alternative 3′-Terminal Exon ». Molecular and Cellular Biology 19, no 1 (1 janvier 1999) : 78–85. http://dx.doi.org/10.1128/mcb.19.1.78.
Texte intégralRésumé :
ABSTRACT Polypyrimidine tract-binding protein (PTB) is an abundant vertebrate hnRNP protein. PTB binding sites have been found within introns both upstream and downstream of alternative exons in a number of genes that are negatively controlled by the binding of PTB. We have previously reported that PTB binds to a pyrimidine tract within an RNA processing enhancer located adjacent to an alternative 3′-terminal exon within the gene coding for calcitonin and calcitonin gene-related peptide. The enhancer consists of a pyrimidine tract and CAG directly abutting on a 5′ splice site sequence to form a pseudoexon. Here we show that the binding of PTB to the enhancer pyrimidine tract is functional in that exon inclusion increases when in vivo levels of PTB increase. This is the first example of positive regulation of exon inclusion by PTB. The binding of PTB was antagonistic to the binding of U2AF to the enhancer-located pyrimidine tract. Altering the enhancer pyrimidine tract to a consensus sequence for the binding of U2AF eliminated enhancement of exon inclusion in vivo and exon polyadenylation in vitro. An additional PTB binding site was identified close to the AAUAAA hexanucleotide sequence of the exon 4 poly(A) site. These observations suggest a dual role for PTB in facilitating recognition of exon 4: binding to the enhancer pyrimidine tract to interrupt productive recognition of the enhancer pseudoexon by splicing factors and interacting with the poly(A) site to positively affect polyadenylation.
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Le Sommer, Caroline, Michelle Lesimple, Agnès Mereau, Severine Menoret, Marie-Rose Allo et Serge Hardy. « PTB Regulates the Processing of a 3′-Terminal Exon by Repressing both Splicing and Polyadenylation ». Molecular and Cellular Biology 25, no 21 (1 novembre 2005) : 9595–607. http://dx.doi.org/10.1128/mcb.25.21.9595-9607.2005.
Texte intégralRésumé :
ABSTRACT The polypyrimidine tract binding protein (PTB) has been described as a global repressor of regulated exons. To investigate PTB functions in a physiological context, we used a combination of morpholino-mediated knockdown and transgenic overexpression strategies in Xenopus laevis embryos. We show that embryonic endoderm and skin deficient in PTB displayed a switch of the α-tropomyosin pre-mRNA 3′ end processing to the somite-specific pattern that results from the utilization of an upstream 3′-terminal exon designed exon 9A9′. Conversely, somitic targeted overexpression of PTB resulted in the repression of the somite-specific exon 9A9′ and a switch towards the nonmuscle pattern. These results validate PTB as a key physiological regulator of the 3′ end processing of the α-tropomyosin pre-mRNA. Moreover, using a minigene strategy in the Xenopus oocyte, we show that in addition to repressing the splicing of exon 9A9′, PTB regulates the cleavage/polyadenylation of this 3′-terminal exon.
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Kim, J., J. J. Yim, S. Wang et D. Dorsett. « Alternate use of divergent forms of an ancient exon in the fructose-1,6-bisphosphate aldolase gene of Drosophila melanogaster ». Molecular and Cellular Biology 12, no 2 (février 1992) : 773–83. http://dx.doi.org/10.1128/mcb.12.2.773-783.1992.
Texte intégralRésumé :
The fructose-1,6-bisphosphate aldolase gene of Drosophila melanogaster contains three divergent copies of an evolutionarily conserved 3' exon. Two mRNAs encoding aldolase contain three exons and differ only in the poly(A) site. The first exon is small and noncoding. The second encodes the first 332 amino acids, which form the catalytic domain, and is homologous to exons 2 through 8 of vertebrates. The third exon encodes the last 29 amino acids, thought to control substrate specificity, and is homologous to vertebrate exon 9. A third mRNA substitutes a different 3' exon (4a) for exon 3 and encodes a protein very similar to aldolase. A fourth mRNA begins at a different promoter and shares the second exon with the aldolase messages. However, two exons, 3a and 4a, together substitute for exon 3. Like exon 4a, exon 3a is homologous to terminal aldolase exons. The exon 3a-4a junction is such that exon 4a would be translated in a frame different from that which would produce a protein with similarity to aldolase. The putative proteins encoded by the third and fourth mRNAs are likely to be aldolases with altered substrate specificities, illustrating alternate use of duplicated and diverged exons as an evolutionary mechanism for adaptation of enzymatic activities.
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Kim, J., J. J. Yim, S. Wang et D. Dorsett. « Alternate use of divergent forms of an ancient exon in the fructose-1,6-bisphosphate aldolase gene of Drosophila melanogaster. » Molecular and Cellular Biology 12, no 2 (février 1992) : 773–83. http://dx.doi.org/10.1128/mcb.12.2.773.
Texte intégralRésumé :
The fructose-1,6-bisphosphate aldolase gene of Drosophila melanogaster contains three divergent copies of an evolutionarily conserved 3' exon. Two mRNAs encoding aldolase contain three exons and differ only in the poly(A) site. The first exon is small and noncoding. The second encodes the first 332 amino acids, which form the catalytic domain, and is homologous to exons 2 through 8 of vertebrates. The third exon encodes the last 29 amino acids, thought to control substrate specificity, and is homologous to vertebrate exon 9. A third mRNA substitutes a different 3' exon (4a) for exon 3 and encodes a protein very similar to aldolase. A fourth mRNA begins at a different promoter and shares the second exon with the aldolase messages. However, two exons, 3a and 4a, together substitute for exon 3. Like exon 4a, exon 3a is homologous to terminal aldolase exons. The exon 3a-4a junction is such that exon 4a would be translated in a frame different from that which would produce a protein with similarity to aldolase. The putative proteins encoded by the third and fourth mRNAs are likely to be aldolases with altered substrate specificities, illustrating alternate use of duplicated and diverged exons as an evolutionary mechanism for adaptation of enzymatic activities.
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Parra, Marilyn K., Sherry L. Gee, Mark J. Koury, Narla Mohandas et John G. Conboy. « Alternative 5′ exons and differential splicing regulate expression of protein 4.1R isoforms with distinct N-termini ». Blood 101, no 10 (15 mai 2003) : 4164–71. http://dx.doi.org/10.1182/blood-2002-06-1796.
Texte intégralRésumé :
Abstract Among the alternative pre-mRNA splicing events that characterize protein 4.1R gene expression, one involving exon 2′ plays a critical role in regulating translation initiation and N-terminal protein structure. Exon 2′ encompasses translation initiation site AUG1 and is located between alternative splice acceptor sites at the 5′ end of exon 2; its inclusion or exclusion from mature 4.1R mRNA regulates expression of longer or shorter isoforms of 4.1R protein, respectively. The current study reports unexpected complexity in the 5′ region of the 4.1R gene that directly affects alternative splicing of exon 2′. Identified far upstream of exon 2 in both mouse and human genomes were 3 mutually exclusive alternative 5′ exons, designated 1A, 1B, and 1C; all 3 are associated with strong transcriptional promoters in the flanking genomic sequence. Importantly, exons 1A and 1B splice differentially with respect to exon 2′, generating transcripts with different 5′ ends and distinct N-terminal protein coding capacity. Exon 1A-type transcripts splice so as to exclude exon 2′ and therefore utilize the downstream AUG2 for translation of 80-kDa 4.1R protein, whereas exon 1B transcripts include exon 2′ and initiate at AUG1 to synthesize 135-kDa isoforms. RNA blot analyses revealed that 1A transcripts increase in abundance in late erythroblasts, consistent with the previously demonstrated up-regulation of 80-kDa 4.1R during terminal erythroid differentiation. Together, these results suggest that synthesis of structurally distinct 4.1R protein isoforms in various cell types is regulated by a novel mechanism requiring coordination between upstream transcription initiation events and downstream alternative splicing events.
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Lou, H., Y. Yang, G. J. Cote, S. M. Berget et R. F. Gagel. « An intron enhancer containing a 5' splice site sequence in the human calcitonin/calcitonin gene-related peptide gene. » Molecular and Cellular Biology 15, no 12 (décembre 1995) : 7135–42. http://dx.doi.org/10.1128/mcb.15.12.7135.
Texte intégralRésumé :
Regulation of calcitonin (CT)/calcitonin gene-related peptide (CGRP) RNA processing involves the use of alternative 3' terminal exons. In most tissues and cell lines, the CT terminal exon is recognized. In an attempt to define regulatory sequences involved in the utilization of the CT-specific terminal exon, we performed deletion and mutation analyses of a mini-gene construct that contains the CT terminal exon and mimics the CT processing choice in vivo. These studies identified a 127-nucleotide intron enhancer located approximately 150 nucleotides downstream of the CT exon poly(A) cleavage site that is required for recognition of the exon. The enhancer contains an essential and conserved 5' splice site sequence. Mutation of the splice site resulted in diminished utilization of the CT-specific terminal exon and increased skipping of the CT exon in both the mini-gene and in the natural CT/CGRP gene. Other components of the intron enhancer modified utilization of the CT-specific terminal exon and were necessary to prevent utilization of the 5' splice site within the intron enhancer as an actual splice site directing cryptic splicing. Conservation of the intron enhancer in three mammalian species suggests an important role for this intron element in the regulation of CT/CGRP processing and an expanded role for intronic 5' splice site sequences in the regulation of RNA processing.
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Datson, Nicole A., Geoffrey M. Duyk, Gert-Jan B. van Ommen et Johan T. Den Dunnen. « Specific isolation of 3′-terminal exons of human genes by exon trapping ». Nucleic Acids Research 22, no 20 (1994) : 4148–53. http://dx.doi.org/10.1093/nar/22.20.4148.
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Tabaska, J. E., R. V. Davuluri et M. Q. Zhang. « Identifying the 3'-terminal exon in human DNA ». Bioinformatics 17, no 7 (1 juillet 2001) : 602–7. http://dx.doi.org/10.1093/bioinformatics/17.7.602.
Texte intégralThèses sur le sujet "3’ terminal exon"
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Anquetil, Vincent. « Régulation tissulaire de l'épissage alternatif : Caractérisation fonctionnelle d'une séquence activatrice de la maturation d'un exon 3' terminal ». Phd thesis, Université Rennes 1, 2009. http://tel.archives-ouvertes.fr/tel-00462347.
Texte intégralRésumé :
La maturation des ARN pré-messagers est le fruit d'un ensemble de processus nucléaires interconnectés qui sont soumis à de nombreuses régulations. L'épissage alternatif des exons 3' terminaux joue un rôle majeur dans l'expression des gènes car il permet de réguler qualitativement et quantitativement leur expression. Nous étudions les déterminants de la régulation tissulaire de l'épissage et de la polyadénylation en utilisant comme modèle le gène de la tropomyosine α de xénope. Ce gène contient, dans sa région 3' terminale, un exon composite interne/3' terminal nommé 9A9' qui est utilisé comme exon 3' terminal dans les somites et est sauté dans les tissus non musculaires dans l'embryon de xénope. L'utilisation de minigènes contenant une portion de la région 3' terminale du gène de la tropomyosine α placée sous le contrôle de promoteurs tissuspécifiques a permis d'identifier deux éléments introniques régulant l'utilisation de l'exon 9A9'. L'un nommé 150PY est répresseur, l'autre appelé UTE est activateur. L'élément 150PY réprime l'utilisation de l'exon 9A9' dans les cellules non musculaires. Des approches biochimiques et in vivo ont montré que la protéine PTB se fixe sur cet élément et inhibe les réactions d'épissage et de clivage/polyadénylation de l'exon 9A9'. Afin de caractériser la fonction de l'élément activateur UTE, nous avons bloqué son accessibilité dans les embryons à l'aide d'oligonucléotides morpholinos antisens. Nos résultats montrent que l'UTE active l'utilisation de l'exon 9A9' en tant qu'exon 3' terminal en favorisant la reconnaissance du site 3' d'épissage, du signal de polyadénylation et du point de branchement. Ces résultats suggèrent que l'UTE favorise la fixation de la snRNPU2 sur le point de branchement qui à son tour stabilise la liaison du complexe de clivage/polyadénylation sur le signal de polyadénylation permettant ainsi la définition de l'exon 9A9' en tant qu'exon terminal. La PTB prévient l'utilisation de l'UTE dans les cellules non musculaires à l'inverse de certaines protéines SR qui favorisent la sélection de l'exon 9A9' de manière dépendante de cette séquence. Pour caractériser les mécanismes moléculaires impliqués dans la fonction de l'UTE nous avons recherché les facteurs recrutés sur cette séquence. Ces expériences montrent que la protéine ESRP2 est spécifiquement recrutée sur un ARN contenant l'UTE en présence de PTB. ESRP2 est exprimée uniquement dans les cellules épithéliales et pourrait participer avec la PTB à la spécificité tissulaire de la répression de l'exon 9A9'. L'ensemble de ces résultats suggèrent que la régulation tissulaire de l'exon 9A9' est basée sur une compétition de fixation entre des facteurs activateurs et inhibiteurs sur la séquence régulatrice UTE.
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Anquetil, Vincent. « Régulation tissulaire de l’épissage alternatif : caractérisation fonctionnelle d’une séquence activatrice de la maturation d’un exon 3’ terminal ». Rennes 1, 2009. https://theses.hal.science/tel-00462347.
Texte intégralRésumé :
L’épissage alternatif des exons 3’ terminaux permet de réguler qualitativement et quantitativement la production d’ARN messagers. Nous étudions les déterminants de la régulation tissulaire de l’épissage et de la polyadénylation en utilisant comme modèle le gène de la tropomyosine α de xénope qui contient, dans sa région 3’ terminale, l’exon composite interne/3’ terminal 9A9’, dont l’expression est tissu-spécifique. Les études in vivo précédemment réalisées au laboratoire ont permis d’identifier un élément intronique qui réprime l’exon 9A9’ dans les cellules non musculaires. La protéine PTB se fixe sur cet élément et inhibe les réactions d’épissage et de clivage/polyadénylation de l’exon 9A9’. Une séquence activatrice a également été identifiée. Afin de caractériser fonctionnellement cet élément activateur nous avons bloqué son accessibilité dans les embryons de xénope à l’aide de morpholinos spécifiques. Nos résultats a montrent que cet élément activateur est nécessaire à l’utilisation de l’exon 9A9’ en tant qu’exon 3’ terminal dans le myotome. Nous avons également démontré que la PTB prévient son utilisation dans les cellules non musculaires à l’inverse de certaines protéines SR qui favorisent la sélection de l’exon 9A9’ de manière dépendante de cette séquence. Les mécanismes moléculaires de l’activation ont été étudiés in vitro en déterminant la composition protéique des complexes recrutés sur cette séquence. Nous avons identifié une protéine qui participerait à la répression de l’exon 9A9’spécificiquement dans les tissus non musculairesThe alternative splicing of 3' terminal exons regulates qualitatively and quantitatively the production of messenger RNA. To study the determinants of tissue specific splicing and polyadenylation we use the xenopus α-tropomyosin gene as a model system. This gene contain a composite internal/3’ terminal exon (exon 9A9’) that is differentially processed depending on the embryonic tissue. Previous in vivo studies identified an intronic element that represses exon 9A9’ in non muscle cells. The protein PTB binds to this element and inhibits both the splicing and polyadenylation of exon 9A9’. An enhancer element was also identified. To functionally characterize in vivo this activating sequence we used targeted morpholino nucleotides to mask it. We demonstrated that the enhancer element is required for the specific usage of exon 9A9’ as a 3’ terminal exon in the myotome. We also demonstrate that PTB prevents the activity of this element in non muscle cells whereas a sub-class of SR proteins promotes the selection of exon 9A9’ in an enhancer element dependent way. The molecular mechanisms of activation were studied in vitro by analysing the composition of the protein complexes bound to the enhancer element. We identified one protein which could be involved in the repression of exon 9A9' specifically in non-muscle cells
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FONTANA, GABRIELE ALESSANDRO. « Mitochondrial stress deregulates the expression of Brahma, a chromatin - remodeling factor that controls transcription and splicing of genes involved in axon growth and guidance ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/29856.
Texte intégralRésumé :
The human protein Brahma (Brm), encoded by the SMARCA2 gene, is one of the two mutually exclusive ATPase subunits of the mammalian SWI/SNF-BAF chromatin-remodelling complex. Brm-containing BAF complexes are enriched in neurons, where they play crucial roles in the regulation of genes involved in neuronal differentiation. Moreover, it has been reported that Brm associates with components of the spliceosome to regulate the inclusion of alternative internal exons.
While investigating with splicing-sensitive microarrays the gene expression changes triggered by mitochondrial stress, I found that Brm is strongly downregulated in SH-SY5Y human neuroblastoma cells overexpressing the SOD1 (G93A) protein, one of the genetic causes of Amyotrophic Lateral Sclerosis (ALS). I found that this downregulation is due to a mitochondrial stress-induced impairment in the SMARCA2 promoter activity.
Among the genes deregulated at the splicing level by SOD1 (G93A) expression, I identified several targets that are regulated by alternative 3’ terminal exon usage in a Brm-dependent manner. Specifically, I found that Brm promotes the skipping of the proximal terminal exon in five out of six genes that were analyzed. In order to define the molecular mechanism that allow to Brm to modulate the choice of alternative 3’ terminal exons, I used one of these genes, RPRD1A, as a model. I found that Brm inhibits the choice of the proximal RPRD1A last exon by directly localizing in its genomic region. In turn, the absence of Brm at the level of the proximal last exon is concomitant with a change in the processivity of the RNA Polymerase II, an observation consistent with the “terminal exon pausing” event. I hypothesized a model where Brahma may recruit the Bard1-Cstf complex on the RPRD1A proximal last exon, a complex known to inhibit the 3’ end processing of the pre-mRNA. These observations suggest an inhibitory role for Brm, which is exerted both at the level of the cotranscriptional choice of the proximal last exon and at the level of the 3’ end pre-mRNA processing.
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Hamon, Gouault Sandra. « Etude de la maturation différentielle du gène alpha-fast tropomyosine chez xénopus Laevis : identifications d'éléments en cis régulant l'utilisation d'un exon composite interne/3' terminal ». Rennes 1, 2002. http://www.theses.fr/2002REN10046.
Texte intégralRésumé :
L'exon 9A/9' du gène de l'alpha-tropomyosine de Xenopus laevis est utilisé en tant qu'exon 3' terminal dans les cellules musculaires embryonnaires ou en tant qu'exon interne dans les muscles striés embryonnaires et adultes. Il est par contre exclu dans les cellules non musculaires. L'exon 9A/9' se caractérise par des sites d'épissage et un signal de polyadénylation suboptimaux ainsi que par un point de branchement éloigné situé à 274 pb en amont du site d'épissage 3'. Une approche par transgenèse transitoire dans l'embryon a permis de mettre en évidence deux éléments régulateurs chevauchants en amont de l'exon 9A/9'. Un élément répresseur correspondant à des motifs consensuels de liaison à la PTB réprime l'utilisation de cet exon dans les cellules non musculaires. Un élément activateur correspondant à un motif conservé chez les oiseaux et les mammifères, jouxté de plusieurs pseudo points de branchement favorise la sélection de l'exon 9A/9' en tant qu'exon terminal dans les cellules musculaires embryonnaires.
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ARNAULT, FREDERIC. « Contribution a l'etude du gene de la lipoproteine lipase (lpl) : etude de la partie 3' terminale du gene (exon 9-exon 10) ». Paris 6, 1997. http://www.theses.fr/1997PA066203.
Texte intégralRésumé :
Le gene de la lipoproteine lipase (lpl) code un enzyme triacylglycerol hydrolase (ec 3. 1. 1. 34) a role central dans le metabolisme des lipoparticules riches en triglycerides : il reste de nombreuses imprecisions quant aux motifs moleculaires participant aux interactions de la lpl avec ses effecteurs. Les regulations intervenant sur l'expression du gene, ou l'activite lpl, sont tres complexes et encore mal precisees. La lpl est impliquee dans certaines pathologies complexes : obesite, diabete, atherosclerose. Dans un travail preliminaire nous avons compare les sequences lpl actuellement connues (neuf especes), afin de mettre en evidence des zones de similitudes ou des regions specifiques d'especes. Nos comparaisons montrent que la plus longue identite de sequence en acides amines est codee par une sequence entre la fin de l'exon 2 et le debut de l'exon 3. Ceci montre l'importance de cette region qui code, en particulier, la boucle -5 du site actif. L'exon 10, entierement non traduit chez les 8 mammiferes etudies, contient certaines deletions caracteristiques d'especes, insertions, elements riches en a ou a+t. Notre objectif a ete ensuite d'etudier la region 3' terminale lpl exon 9-exon 10 qui est encore peu connue dans ses proprietes fonctionnelles. Cela nous a permis de rapporter ici un nouveau deficit lpl, a cote du releve des anomalies naturelles de la lpl connues actuellement. Ce deficit serait lie a une recombinaison intron- sequence alu. Nous avons voulu determiner si le codon tga clive entre l'exon 9 et l'exon 10 des mammiferes, code une selenocysteine conferant un avantage anti-oxydant a la lpl. Nos etudes suggerent que ce codon tga ne code pas une selenocysteine, mais elles clarifient la structure de la jonction exon 9-exon 10 du gene de la lpl du point de vue de l'evolution (codons aga pour le poisson -17 acides amines codes en plus- ; ggt pour le poulet -15 acides amines codes en plus-).
Chapitres de livres sur le sujet "3’ terminal exon"
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Krizman, David B. « Gene Identification by 3′ Terminal Exon Trapping ». Dans Genetic Engineering, 49–56. Boston, MA : Springer US, 1996. http://dx.doi.org/10.1007/978-1-4899-1766-9_4.
Texte intégralActes de conférences sur le sujet "3’ terminal exon"
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Bernaedi, F., V. Bertagnolo, S. Bartolai, L. Rossi, F. Panicucci et F. Conconi. « A POINT MUTATION AND A GENE DELETION OF FVIII GENE IN SEVERE HAEMOPHILIA ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644047.
Texte intégralRésumé :
The presence of Factor VIII (FVIII) gene lesions has been investigated in 100 haemophilia A patients using cDNA probes for the 3'part of FVIII gene (exons 14-26 ).In two related severe patients without inhibitor a deletion removesthe exon 26; the gene lesion has been confirmed with several restriction enzymes and has been shown by densitometry of the autoradiographic pattern in a woman of the same family. The complete deletionof the exon 26 has been described by Gitschier et al. in a patient with inhibitor. Thus the comparison of the end points of the two deletions could help to define the mechanism originating these gene lesions and the relation between gene lesions and the presence of antibody.In a patient with severe Haemophilia and without inhibitor a mutation removing the TaqI site in the exon 24 and originating an abnormal band of 4.2 Kb has been found. A C→T transition in this TaqI site, originating a nonsense codon and a new Hindlll site, has been reported by Gitschier et al in a patient presenting inhibitor. The DNA from our patient tested with Hindlll shows a normal pattern thus indicating a C→T transition in the antisense strand. This mutation should causean aminoacid change (CGA→CAA, Arg→Gln) possiblyresponsible for the FVIII inactivation but that does not remove theantigenic determinants present in the COOH terminal part of FVIII.In addition the same mutation has been observed in an unrelated (asdemonstrated by RFLPs analysis) Italian haemophilic patient confirming the observation of Youssoufian et al that TaqI sites are mutational hot spots in FVIII gene.
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Ploos van Amstel, J. K., A. L. van der Zanden, P. H. Reitsma et R. M. Bertina. « RESTRICTION ANALYSIS AND SOUTHERN BLOTTING OF TOTAL HUMAN DNA REVEALS THE EXISTENCE OF MORE THAN ONE GENE HOMOLOGOUS WITH PROTEIN S cDNA ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644639.
Texte intégralRésumé :
A deficiency in protein S, the cofactor of activated protein C, is associated with an increased risk for the development of venous thrombosis. It is inherited as an autosomal dominant disorder. To improve the detection of heterozygotes in affected families, we have started to search for restriction fragment length polymorphism (RFLP) in the protein S gene. This study revealed the existence of two genes containing sequences homologous to protein S cDNA.Three non-overlapping fragments of clone pSUL5, which codes for the carboxy-terminal part of protein S and contains the complete 3' untranslated region, were isolated and used as probes in search for RFLP of the protein S gene.Surprisingly the non-overlapping probes shared more than one hybridizing band. The hybridization took place under stringent assay conditions.This observation is contradictory to the intron-exon organization of a gene and suggests the existence of two genes, containing sequences homologous with pSUL5. Both genes could be assigned to chromosome 3 by mapping through somatic cell hybrids. Whether two functional protein S genes are present in the human genome remains to be established.
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Loskutoff, D. J., J. Mimuro et C. Hekman. « PLASMINOGEN ACTIVATOR INHIBITOR ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644763.
Texte intégralRésumé :
Plasminogen activation provides an important source of localized proteolytic activity not only during fibrinolysis, but also during ovulation, cell migration, epithelial cell differentiation, tumor invasion and a variety of other physiological processes. Precise regulation of plasminogen activator (PA) activity thus constitutes a critical feature of many biological processes. This control is achieved in large part through the action of specific PA inhibitors (PAIs). Although 4 distinct PAIs have been detected,1the endothelial cellTderived inhibitor (PAI-1) is the only one that efficiently inhibits both urokinase (Kd=2.3×10−13M; Kassoc =1.6×108 M−1s−1) and single-chaintissue-type PA (tPA; Kd=1.3×lO−15 M Kd=3.9×lO7M−1s−1). It also inhibits trypsin (Kassoc=6.8×106M−1 s−1 ) ancl Plasmin (Kassoc=7.6×l05 M−1 s5 Analysis of the effect of PAI-1 on the rate of plasminogen activation revealed a competitive type of inhibition when urokinase was employed but a linear mixed type of inhibition when single chain tPA was employed. These results suggest that the interaction of PAI-1 with tPA, in contrast to its interaction with urokinase, may involve 2 sites on the tPA molecule.PAI-1 has been purified from medium conditioned by cultured bovine aortic endothelial cells and partially characterized. It is a major biosynthetic product of these cells, accounting for as much as 12% of the total protein released by the cells in 24 h. It has an M of 50,000, an isoelectric point of 4.5-5.0, and is immunologically and biochemically related to the rapidly acting inhibitor present in human platelets and in the plasma of some patients at risk to develop thrombotic problems. Although it is relatively stable to conditions which inactivate most protease inhibitors (acid pH, SDS), it is extremely sensitive to oxidants. The molecular cloning of the PAI-1 gene revealed that the mature human protein is 379 amino acids long, contains an NH2-terminal valine, lacks cysteines and has a methionine at the Pi position of it's reactive center. The conversion of this methionine to methionine sulfoxide may be responsible for the rapid inactivation of PAI-1 by oxidants. Human PAI-1 has extensive (30%) homology with α1-antitrypsin and antithrombin III and is thus a member of the serine proteinase inhibitor (serpin) family; a group of related molecules that control the major protease cascades of the blood. The PAI-1 gene is approximately 12.2 kilobase pairs in length and is organized into nine exons and eight introns.The production of PAI-1 by endothelial cells is stimulated by endotoxin, interleukin-1, tumor necrosis factor, and transforming growth factor β(TGFβ). The cells are extremely sensitive to TGFβwith maximal effects (100-fold stimulation) observed with 1-2 ng/ml. These changes were relatively specific for PAI-1, and could be detected at both the protein and the RNA level. Interestingly, TGFgalso stimulated the amount of PAI-1 present in the extracellular matrix (ECM) of BAEs. PAI-1 was one of the primary ECM components of these cells, constituting 10-20% of the ECM proteins detected after SDS-PAGE.One of the most unusual properties of PAI-1 is that it exists in blood and in various cellular samples in both an active and an inactive (latent) form, the ratio depending on the source. The latent form can be converted into the active one by treatment with denaturants like SDS or guanidine-HCl. Although the majority of the cell-associated PAI-1 is active, it rapidly decays (t1/2=3 h) into the latent form once it is released from the cells. In contrast, the half-life of ECM associated PAI-1 was greater than 24 h. These data suggest that PAI-1 is produced by BAEs in an active form, and is then either released into the medium where it is rapidly inactivated, or released into the subendothelium where it binds to ECM. The specific binding of PAI-1 to ECM protects it from this inactivation.