Circularization of an RNA template via long-range base pairing is critical for hepadnaviral reverse transcription.
Although an overall genetic strategy for hepadnaviral reverse transcription has been established, the mechanism that underlies the minus-strand transfer is still poorly defined. We and others independently identified a novel cis-acting element, termed beta or varphi, respectively, that is critical for the minus-strand DNA synthesis of hepatitis B virus. A 5'-3', long-range interaction of the RNA template was proposed that involves the 5' epsilon sequence (encapsidation signal) and the 3' beta/varphi sequence. We subjected the hypothesized base pairing to genetic analysis. The data indicated that mutations abrogating the hypothesized base pairing markedly impaired minus-strand DNA synthesis, while compensatory mutations that restored the base pairing rescued the minus-strand DNA synthesis. These results demonstrated the critical role of the 5'-3', long-range interaction in minus-strand DNA synthesis. We speculate that such a long-range interaction may precisely juxtapose a donor to an acceptor during minus-strand transfer.
Shin
Myeong-Kyun
MK
Department of Biochemistry, Yonsei University, 134 Shinchondong, Seodaemungu, Seoul, 120-749, South Korea.
Kim
Jong-Hoon
JH
Ryu
Dong-Kyun
DK
Ryu
Wang-Shick
WS
D020029:Base Pairing; D001483:Base Sequence; D045744:Cell Line, Tumor; D004270:DNA, Circular / Q000096:biosynthesis; D004279:DNA, Viral / Q000096:biosynthesis*; D006515:Hepatitis B virus / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D012367:RNA, Viral / Q000235:genetics*; D048348:Reverse Transcription; D013698:Templates, Genetic
D004270:DNA, Circular; D004279:DNA, Viral; D012367:RNA, Viral