DESCRIPTION (Adapted from investigator's abstract): The two cis-acting elements required for 3'-processing of pre-mRNA include the highly conserved AAUAAA hexamer and an amorphous U-or GU-rich downstream element. HIV-1 genome presents an interesting dilemma in that it selects 3'-poly (A) site while disregarding a canonical poly (A) site processing signal present at the 5'- end. An upstream element, some 76 nucleotides 3'- of AAUAAA hexamer, which is unique to the 3'poly (A) site, is required for efficient processing of the 3'- core poly (A). The upstream element serves to enhance 3'-processing by promoting stable binding of the processing factors, CPSF, (cleavage and polyadenylation specificity factor), at the core poly (A) site. The application aims to provide further insight into the sequence and structural elements of HIV-1 poly (A) site selection in order to design specific processing factor for the targeting of the 3'-processing machinery to the 5'- core poly (A) site. Such an accomplishment will block the synthesis of functional viral mRNAs. The PI proposes to develop strategies for targeting 3'-processing to multiple sites within the HIV-1 pre-mRNA, which will serve to restrict viral gene expression.