Restoration of both structure and function to a defective poly(A) site by in vitro selection. NLM AIDSLINE Important note: Information in this article was accurate in 1997. The state of the art may have changed since the publication date.

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Restoration of both structure and function to a defective poly(A) site by in vitro selection.

J Biol Chem. 1996 Dec 27;271(52):33654-63. Unique Identifier : AIDSLINE MED/97126013
Graveley BR; Fleming ES; Gilmartin GM; Department of Microbiology and Molecular Genetics, Markey Center for; Molecular Genetics, Stafford Hall, University of Vermont, Burlington,; Vermont 05405, USA. ggilmart@moose.uvm.edu

Abstract: Efficient cleavage and polyadenylation at the human immunodeficiency virus type-1 (HIV-1) poly(A) site requires an upstream 3'-processing enhancer to overcome the suboptimal sequence context of the AAUAAA hexamer. The HIV-1 3'-processing enhancer functions to stabilize the association of the pre-mRNA with cleavage and polyadenylation specificity factor (CPSF), the factor responsible for recognition of the AAUAAA hexamer. Intriguingly, in the absence of the 3'-processing enhancer, CPSF binding and polyadenylation efficiency could be restored to near wild-type levels upon replacement of the 14-nucleotide region immediately 5' of the HIV-1 AAUAAA hexamer (the B segment) by the analogous sequences from the efficient adenovirus L3 poly(A) site. To further investigate the contributions of RNA sequence and structure to poly(A) site recognition, we have used an in vitro selection system to identify B segment sequences that enhance the polyadenylation efficiency of a pre-cleaved RNA lacking a 3'-processing enhancer. The final RNA selection pool was composed of two predominant classes of RNAs. Nuclease probing revealed that the selected sequences restored an RNA conformation that facilitates recognition of the AAUAAA hexamer by CPSF. These results indicate that both the sequence and structural context of the AAUAAA hexamer contribute to poly(A) site recognition by CPSF.
Keywords: *HIV-1/GENETICS *Poly A/CHEMISTRYKWDhiv-1/geneticsKWDpolya/chemistry
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M9741516

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