Hepadnavirus polymerase gene product having RNA-dependent DNA priming and reverse transcriptase activities and methods of measuring the activities thereof

摘要

An enzymatically active, substantially virus-free hepadnavirus polymerase gene product is provided, which possesses a DNA priming function and reverse transcriptase activity, both of which are dependent on the presence of an RNA template and magnesium ions. The hepadnavirus polymerase gene product is produced by in vitro transcription and translation of a hepadnavirus pol gene.PPThe enzymatically active hepadnavirus polymerase gene product is used in rapid in vitro assays to screen potential anti-hepadnaviral agents. An assay for the DNA priming activity of the gene product is provided, wherein covalent attachment of labelled dGTP to the gene product is quantitatively measured. An assay for the reverse transcriptase activity of the gene product is provided, wherein incorporation of nucleotide triphosphates into the nascent DNA minus strand is measured, taking advantage of the covalent attachment of said nascent strand to the polymerase gene product.