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Identification and characterization of HIV‐specific RNase H by monoclonal antibody.
Author(s) -
Hansen J.,
Schulze T.,
Mellert W.,
Moelling K.
Publication year - 1988
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1988.tb02805.x
Subject(s) - rnase h , biology , reverse transcriptase , rnase p , rnase mrp , provirus , retrovirus , microbiology and biotechnology , rna , rna directed dna polymerase , dna polymerase , exonuclease , dna , virology , virus , biochemistry , gene , genome
Human immune deficiency virus (HIV) replicates by conversion of the RNA genome into the double‐stranded DNA provirus. The reverse transcriptase is not the only enzymatic function crucial in DNA‐provirus synthesis. A viral‐coded RNase H activity which specifically degrades RNA in RNA‐DNA hybrids has been shown to be essential as well. Here we demonstrate that the HIV‐reverse transcriptase which consists of a two‐polypeptide complex, p66 and p51, copurifies with an RNase H activity which exhibits properties of a processive exonuclease. Only the p66 molecule, not p51, is active as polymerase as evidenced by activated gel analysis. p66 exhibits RNase H activity when precipitated as immune complex by a monoclonal antibody raised against a bacterially expressed carboxy‐terminal portion of p66. The monoclonal antibody which does not interfere with enzyme activity also precipitates a second population of molecules with RNase H activity which is of low mol. wt, p15. This RNase H appears therefore to be derived from the carboxy terminus of p66 during processing to the p51 polypeptide. It exhibits low template‐binding ability and is of a non‐processing mode of action which may be due to the absence of the reverse transcriptase domain. These results lend experimental support to the hypothesis that the RNase H gene maps at the carboxy terminus of the reverse transcriptase. Since both RNase H populations are virus‐coded they may be essential for retrovirus replication in general and useful targets for chemotherapeutic agents.