Avian myeloblastosis virus and Maloney murlne leukemia virus RNase H reverse transcriptases pause when they encounter a 2′–5′ linkage or a 2′-thiophosphate In their template RNAs, but eventually read through these backbone modifications. Both reverse transcriptases pause after the 2′–5′ linkage but before the 2′-thlophosphate. These results suggest that in the absence of precise information concerning the behavior of a given reverse transcriptase with respect to a particular lesion or modification, caution should be exercised in the interpretation of primer extension data that is being used to determine the existence of, or map the position of, a crosslink, site of chemical modification or non-standard linkage in an RNA template.

Author notes

+Present address: Whitehead Institute for Biomedical Research, Cambridge, MA 04, USA