Document 0952
 DOCN  M9540952
 TI    CPSF recognition of an HIV-1 mRNA 3'-processing enhancer: multiple
       sequence contacts involved in poly(A) site definition.
 DT    9504
 AU    Gilmartin GM; Fleming ES; Oetjen J; Graveley BR; Department of
       Microbiology and Molecular Genetics, Markey Center; for Molecular
       Genetics, University of Vermont, Burlington 05405.
 SO    Genes Dev. 1995 Jan 1;9(1):72-83. Unique Identifier : AIDSLINE
       MED/95129835
 AB    The endonucleolytic cleavage and polyadenylation of a pre-mRNA in
       mammalian cells requires two cis-acting elements, a highly conserved
       AAUAAA hexamer and an amorphous U- or GU-rich downstream element, that
       together constitute the core poly(A) site. The terminal redundancy of
       the HIV-1 pre-mRNA requires that the processing machinery disregard a
       core poly(A) site at the 5' end of the transcript, and efficiently
       utilize an identical signal that resides near the 3' end. Efficient
       processing at the 3' core poly(A) site, both in vivo and in vitro, has
       been shown to require sequences 76 nucleotides upstream of the AAUAAA
       hexamer. In this report we demonstrate that this HIV-1 upstream element
       interacts directly with the 160-kD subunit of CPSF (cleavage
       polyadenylation specificity factor), the factor responsible for the
       recognition of the AAUAAA hexamer. The presence of the upstream element
       in the context of the AAUAAA hexamer directs the stable binding of CPSF
       to the pre-mRNA and enhances the efficiency of poly(A) addition in
       reactions reconstituted with purified CPSF and recombinant poly(A)
       polymerase. Our results indicate that the dependence of HIV-1 3'
       processing on upstream sequences is a consequence of the suboptimal
       sequence context of the AAUAAA hexamer. We suggest that poly(A) site
       definition involves the recognition of multiple heterogeneous sequence
       elements in the context of the AAUAAA hexamer.
 DE    Enhancer Elements (Genetics)/*GENETICS  Hela Cells  Human
       HIV-1/*GENETICS  Poly A/BIOSYNTHESIS  Protein Binding  RNA
       Precursors/METABOLISM  *RNA Processing, Post-Transcriptional
       RNA-Binding Proteins/*METABOLISM  RNA, Messenger/BIOSYNTHESIS  RNA,
       Viral/*METABOLISM  Support, Non-U.S. Gov't  Support, U.S. Gov't, P.H.S.
       JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).