REGULATION OF POLYADENYLATION--THE U1A/U1 SNRNP PARADIGM

Project Details

Description

Post-transcriptional regulation of the processing of eukaryotic pre-mRNA
(splicing, polyadenylation, editing, etc...) is an important control point
in gene expression in eukaryotes. We recently discovered a novel form of
gene regulation where the U1A protein, a component of the U1 snRNP
involved in pre-mRNA splicing, negatively autoregulates its own production
by binding to and inhibiting the polyadenylation of its own pre-mRNA (38-
41). The complex between U1A and the U1A pre-mRNA binds to and blocks the
activity of polyA polymerase (PAP), the enzyme which catalyzes addition of
the polyA tail. U1A autoregulation is the first example of its kind. As
part of the original proposal we characterized another system in which the
U1 snRNA-associated 70K protein inhabits polyadenylation by also
inhabiting PAP. Unlike the case of U1A, however, 70K inhibits PAP while
being indirectly bound to the pre-mRNA through the U1 snRNP complex which
is base-paired to the pre-mRNA. Surprisingly, even though U1A is present
in the U1 snRNP complex, the PAP-inhibitory activity resides entirely with
the 70K protein. The discovery that the polyadenylation inhibitory motifs
in both U1A and 70K are conserved and are found in other proteins suggests
that polyadenylation regulation via PAP inhibition will be more widespread
than previously thought.

The framework for this proposal is to use the examples of U1A and 70K as
a basis to achieve the following goals which are: 1) to determine how
prevalent inhibition of PAP is as a regulatory mechanism by finding
additional examples, 2) to characterize the cis- and transacting sequence
motifs in order to define a family of proteins able to control gene
expression via inhibition of PAP, and 3) to determine whether this type pf
regulation can be used to control expression of heterologous genes in
vivo. The achievement of this proposal will advance fundamental knowledge
of pre-mRNA processing and indicate the generality of regulation of
polyadenylation by U1 snRNA-associated proteins. By elucidating the
molecular mechanisms by which these two splicing-associated proteins
control the polyadenylation machinery, we will provide insight into the
competition between splicing and polyadenylation that in many cases forms
the basis for how alterative processing of pre-mRNAs is governed.
StatusFinished
Effective start/end date1/1/995/31/08

Funding

  • National Institute of General Medical Sciences: $398,721.00
  • National Institute of General Medical Sciences: $329,862.00
  • National Institute of General Medical Sciences: $320,404.00
  • National Institute of General Medical Sciences: $399,023.00
  • National Institute of General Medical Sciences: $339,603.00
  • National Institute of General Medical Sciences: $400,780.00
  • National Institute of General Medical Sciences: $311,222.00
  • National Institute of General Medical Sciences: $397,991.00

ASJC

  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Genetics
  • Molecular Biology

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