An unusual mechanism of self-primed reverse transcription requires the RNase H domain of reverse transcriptase to cleave an RNA duplex.
The reverse transcription of retroviruses and long terminal repeat-containing retrotransposons requires that tRNA species serve as primers. We recently reported that the long terminal repeat-containing retrotransposon Tf1 is a unique exception in that reverse transcription is independent of tRNA and is instead initiated by a self-priming mechanism. The first 11 bases of the Tf1 transcript fold back and anneal to the primer binding site in a process that results in the priming of minus-strand strong-stop DNA. Data presented here demonstrate that a cleavage occurs between the 11th and 12th bases of the transcript, resulting in the generation of the primer. Mutagenesis experiments presented here indicate that the RNase H domain of the Tf1 reverse transcriptase is required for the cleavage reaction, suggesting that this RNase H may have the novel ability to cleave double-stranded RNA at the end of a duplexed region.
Levin
H L
HL
Laboratory of Eukaryotic Gene Regulation, National Institute of Child Health and Human Development, Bethesda, Maryland 20892, USA. Henry_Levin@nih.gov
D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers; D054303:HIV Reverse Transcriptase / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000737:chemistry; D012367:RNA, Viral / Q000096:biosynthesis / Q000737:chemistry; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry / Q000378:metabolism*; D012190:Retroviridae / Q000201:enzymology*; D016914:Ribonuclease H / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D017931:DNA Primers; D012333:RNA, Messenger; D012367:RNA, Viral; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase; D016914:Ribonuclease H