scholarly journals Polypyrimidine Tract-binding Protein Is Involvedin Vivoin Repression of a Composite Internal/3′ -Terminal Exon of theXenopusα-Tropomyosin Pre-mRNA

2004 ◽  
Vol 279 (21) ◽  
pp. 22166-22175 ◽  
Author(s):  
Sandra Hamon ◽  
Caroline Le Sommer ◽  
Agnès Mereau ◽  
Marie-Rose Allo ◽  
Serge Hardy
Keyword(s):  
Binding Protein ◽  
Polypyrimidine Tract ◽  
Terminal Exon ◽  
Polypyrimidine Tract Binding ◽  
Polypyrimidine Tract Binding Protein

scholarly journals Polypyrimidine Tract-Binding Protein Positively Regulates Inclusion of an Alternative 3′-Terminal Exon

1999 ◽  
Vol 19 (1) ◽  
pp. 78-85 ◽  
Author(s):  
Hua Lou ◽  
David M. Helfman ◽  
Robert F. Gagel ◽  
Susan M. Berget
Keyword(s):  
Binding Protein ◽  
Consensus Sequence ◽  
Polypyrimidine Tract ◽  
Terminal Exon ◽  
Exon Inclusion ◽  
Polypyrimidine Tract Binding ◽  
Polypyrimidine Tract Binding Protein ◽  
Exon 4 ◽  
A Site

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.

scholarly journals PTB Regulates the Processing of a 3′-Terminal Exon by Repressing both Splicing and Polyadenylation

2005 ◽  
Vol 25 (21) ◽  
pp. 9595-9607 ◽  
Author(s):  
Caroline Le Sommer ◽  
Michelle Lesimple ◽  
Agnès Mereau ◽  
Severine Menoret ◽  
Marie-Rose Allo ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Binding Protein ◽  
Specific Pattern ◽  
Polypyrimidine Tract ◽  
Terminal Exon ◽  
Polypyrimidine Tract Binding ◽  
Polypyrimidine Tract Binding Protein ◽  
Physiological Regulator

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.

scholarly journals Polypyrimidine Tract Binding Protein Modulates Efficiency of Polyadenylation

2004 ◽  
Vol 24 (15) ◽  
pp. 6889-6889 ◽  
Author(s):  
Pedro Castelo-Branco ◽  
Andre Furger ◽  
Matthew Wollerton ◽  
Christopher Smith ◽  
Alexandra Moreira ◽  
...  
Keyword(s):  
Binding Protein ◽  
Polypyrimidine Tract ◽  
Polypyrimidine Tract Binding ◽  
Polypyrimidine Tract Binding Protein
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