Electron microscope study of the base sequence homology between simian virus 40 and human papovavirus BK

Abstract

The base sequence homology between the genomes of SV40 and human papovavirus BK (BKV) was studied by a heteroduplex method. When mounted for EM in 30% formamide (Tm [effective temperature] -35.degree. C), BKV/SV40 heteroduplexes were an average of 92% double-stranded and contained only 2 small nonhomologous regions that mapped near the junctions between the early and late regions of the SV40 genome. At higher formamide concentrations, the fraction of duplex DNA in the BKV/SV40 heteroduplexes decreased, indicating significant base mismatching in the homologous regions. The strongest regions of homology were located in the late region.