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U1A inhibits cleavage at the immunoglobulin M heavy-chain secretory poly(A) site by binding between the two downstream GU-rich regions.

ABSTRACT: The immunoglobulin M heavy-chain locus contains two poly(A) sites which are alternatively expressed during B-cell differentiation. Despite its promoter proximal location, the secretory poly(A) site is not expressed in undifferentiated cells. Crucial to the activation of the secretory poly(A) site during B-cell differentiation are changes in the binding of cleavage stimulatory factor 64K to GU-rich elements downstream of the poly(A) site. What regulates this change is not understood. The secretory poly(A) site contains two downstream GU-rich regions separated by a 29-nucleotide sequence. Both GU-rich regions are necessary for binding of the specific cleavage-polyadenylation complex. We demonstrate here that U1A binds two (AUGCN(1-3)C) motifs within the 29-nucleotide sequence and inhibits the binding of cleavage stimulatory factor 64K and cleavage at the secretory poly(A) site.

SUBMITTER: Phillips C

PROVIDER: S-EPMC434241 | biostudies-literature | 2004 Jul

REPOSITORIES: biostudies-literature

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U1A inhibits cleavage at the immunoglobulin M heavy-chain secretory poly(A) site by binding between the two downstream GU-rich regions.

Phillips Catherine C Pachikara Niseema N Gunderson Samuel I SI

Molecular and cellular biology 20040701 14

The immunoglobulin M heavy-chain locus contains two poly(A) sites which are alternatively expressed during B-cell differentiation. Despite its promoter proximal location, the secretory poly(A) site is not expressed in undifferentiated cells. Crucial to the activation of the secretory poly(A) site during B-cell differentiation are changes in the binding of cleavage stimulatory factor 64K to GU-rich elements downstream of the poly(A) site. What regulates this change is not understood. The secretor ...[more]

PMID: 15226420

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