TY - JOUR
T1 - Efficient extension of a misaligned tRNA-primer during replication of the HIV-1 retrovirus
AU - Das, A. T.
AU - Berkhout, B.
PY - 1995
Y1 - 1995
N2 - The human immunodeficiency virus (HIV) and other retroviruses show extensive genomic variation, which is primarily due to error-prone replication by the viral reverse transcriptase (RT) enzymes. RT errors include misincorporation with subsequent extension of the mismatched terminal base, and extension of realigned primer-template duplexes. Whereas both RT-mediated mechanisms have been extensively studied in vitro, almost no in vivo experiments have been performed. In this work, we analyzed the ability of HIV-1 RT to extend a misaligned tRNA(Lys3) primer in vivo. This tRNA binds with its 3'-terminal 18 nt to a complementary sequence in the viral genome, referred to as the primer-binding site (PBS). We constructed a series of mutant viral genomes with small insertions or deletions in the PBS sequence, resulting in misalignment of the tRNA primer. Extension of the misaligned primer did occur with reasonable efficiency for some of the mutants, resulting in reversion to the wild-type viral sequence. The infectivity and reversion frequency of the PBS mutants is therefore a measure of the efficiency of extending a misaligned primer in vivo. Using virion-derived primer-template complexes, we also measured the tRNA-priming efficiency in vitro. The combined results show that HIV-1 RT can elongate a misaligned primer and that the efficiency of primer extension is determined by the extent of the mismatch
AB - The human immunodeficiency virus (HIV) and other retroviruses show extensive genomic variation, which is primarily due to error-prone replication by the viral reverse transcriptase (RT) enzymes. RT errors include misincorporation with subsequent extension of the mismatched terminal base, and extension of realigned primer-template duplexes. Whereas both RT-mediated mechanisms have been extensively studied in vitro, almost no in vivo experiments have been performed. In this work, we analyzed the ability of HIV-1 RT to extend a misaligned tRNA(Lys3) primer in vivo. This tRNA binds with its 3'-terminal 18 nt to a complementary sequence in the viral genome, referred to as the primer-binding site (PBS). We constructed a series of mutant viral genomes with small insertions or deletions in the PBS sequence, resulting in misalignment of the tRNA primer. Extension of the misaligned primer did occur with reasonable efficiency for some of the mutants, resulting in reversion to the wild-type viral sequence. The infectivity and reversion frequency of the PBS mutants is therefore a measure of the efficiency of extending a misaligned primer in vivo. Using virion-derived primer-template complexes, we also measured the tRNA-priming efficiency in vitro. The combined results show that HIV-1 RT can elongate a misaligned primer and that the efficiency of primer extension is determined by the extent of the mismatch
U2 - https://doi.org/10.1093/nar/23.8.1319
DO - https://doi.org/10.1093/nar/23.8.1319
M3 - Article
C2 - 7538660
SN - 0305-1048
VL - 23
SP - 1319
EP - 1326
JO - Nucleic Acids Research
JF - Nucleic Acids Research
IS - 8
ER -