Format

Send to

Choose Destination
See comment in PubMed Commons below
Virology. 1996 Jun 15;220(2):290-8.

Mutations within the primer binding site of the human immunodeficiency virus type 1 define sequence requirements essential for reverse transcription.

Author information

  • 1Department of Microbiology, University of Alabama at Birmingham 35294, USA.

Abstract

The primer binding site (PBS) is involved in two stages during the reverse transcription of the retroviral RNA genome. In the early stage, the PBS provides complementary sequences through which tRNA(Lys,3) binds the viral RNA genome to initiate minus-strand DNA synthesis; in the later stages, complementarity between the plus- and minus-strand copies of the PBS is required to facilitate the second template transfer needed to complete reverse transcription. We previously constructed a mutant HIV-1 proviral genome, designated as pHXB2PBS(pheC + 5) (now referred to as pheC + 5), which was used to identify regions of the PBS involved in the initiation and second template transfer steps of reverse transcription. To further define the sequence requirements of the PBS for the initiation of reverse transcription, we have made single nucleotide substitutions within the first six nucleotides of the pheC + 5 PBS. Our results demonstrate that mutations within the first five nucleotides of the PBS which disrupt base paring with tRNA(Lys,3)-PBS results in an noninfectious virus; a G-U base pair at position six of the tRNA(Lys,3)-PBS complex was tolerated. In contrast to the requirements for initiation, we found that complementary binding between only three base pairs of the plus- and minus-strand PBSs was required for the extension of plus-strand DNA during the second template transfer. Furthermore, regions of the minus-strand DNA of up to 24 nucleotides could be looped-out to facilitate the complementarity required for the completion of plus-strand DNA synthesis. Taken together, the results of our studies demonstrate that different features of the PBS with respect to RNA:RNA and DNA:DNA interactions are required for initiation of reverse transcription and the completion of plus-strand DNA synthesis, respectively.

[PubMed - indexed for MEDLINE]
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk