Retrovirus-specific random mutagenesis by a nucleoside 5'-triphosphate analogue, PTP

In a retrovirus replication model system, which consists of in vitro transcription and reverse transcription cycles, 6-(beta-D-ribofuranosyl)-3,4- dihydro-8H-pyrimido[4,5-c][1,2]oxazin-7-one-5'-triphosphate (PTP) induced highly efficient random mutations and this was due to the ambiguous incorporation of PTP by RNA polymerases. The types of mutations were mainly C-to-U or U-to-C transition mutations and the frequency was about 4 x 10(-2)/nucleotide during four cycles of the replication. Since a high mutation rate is harmful to species, PTP may be new candidate for anti-retroviral drugs. N4-aminoCTP and N4-hydroxyCTP were also incorporated ambiguously by RNA polymerase. These compounds may have a potential to induce mutation by the same mechanism as PTP.