Das A T, Klaver B, Berkhout B
Department of Human Retrovirology, University of Amsterdam, The Netherlands.
J Gen Virol. 1997 Apr;78 ( Pt 4):837-40. doi: 10.1099/0022-1317-78-4-837.
Retroviruses use a cellular tRNA molecule as primer for reverse transcription. The complementarity between the 3' end of this tRNA and a sequence near the 5' end of the viral RNA, the primer-binding site (PBS), allows the primer to anneal onto the viral RNA. During reverse transcription 18 nucleotides of the tRNA primer are copied into the viral cDNA, thereby regenerating the PBS sequence of the progeny. Thus, the PBS sequence reveals which primer was used. Human immunodeficiency viruses are known to replicate efficiently with tRNA(Lys3) as primer. Examination of the PBS sequence in natural and laboratory isolates indicates that a variant tRNA(Lys) is occasionally used as primer. This variant, for which the murine genomic sequence was described previously, was termed tRNA(Lys5) and differs from tRNA(Lys3) at five nucleotide positions. These results suggest that HIV uses both tRNA(Lys3) and tRNA(Lys5) molecules as primer, causing a switch of the PBS sequence.
逆转录病毒利用细胞tRNA分子作为逆转录的引物。该tRNA 3'端与病毒RNA 5'端附近的序列（引物结合位点，PBS）之间的互补性，使得引物能够退火结合到病毒RNA上。在逆转录过程中，tRNA引物的18个核苷酸被复制到病毒cDNA中，从而再生子代的PBS序列。因此，PBS序列揭示了所使用的引物。已知人类免疫缺陷病毒以tRNA(Lys3)作为引物高效复制。对天然和实验室分离株中PBS序列的检测表明，一种变异的tRNA(Lys)偶尔也被用作引物。这种变异体的小鼠基因组序列先前已有描述，被称为tRNA(Lys5)，它在五个核苷酸位置上与tRNA(Lys3)不同。这些结果表明，HIV使用tRNA(Lys3)和tRNA(Lys5)分子作为引物，导致PBS序列发生切换。
