An intrastrain variation of a 189-bp repeat region in the human cytomegalovirus replication origin.
A 189-bp repeat has been reported previously to be present in the replication origin (ORI) of Human cytomegalovirus (HCMV) Towne strain and to contain essential and supporting sequences (Chen et al., Arch. Virol. 141, 13301 (1996)). In this study, clones of HCMV strain Towne were isolated and analyzed for the copy number of the 189-bp repeat within its ORI (oriLyt). Southern blot analysis revealed that out of 14 clones, two contained a dimer, two contained a tetramer, and the remaining contained a trimer of the 189-bp repeat. Nucleotide sequence analysis disclosed that, within the dimer and the tetramer, the 189-bp repeat was present in a directly repeated manner. In this way we demonstrated an HCMV intrastrain variation in the copy number of the 189-bp repeat. Dot blot hybridization and growth curve analysis showed that the clones containing the dimer or the tetramer replicated in infected cells with similar efficiencies. We conclude that the HCMV oriLyt with spatial separation of the essential flanking regions by various copy number of the 189-bp repeat acts as ORI in the viral genome.
Chen
Z
Z
Wuhan Institute of Virology, Chinese Academy of Science, Wuhan, Hubei, P.R. China. chenze2005@263.net
Watanabe
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D015139:Blotting, Southern; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000235:genetics* / Q000254:growth & development; D004279:DNA, Viral / Q000235:genetics*; D006801:Humans; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D018741:Replication Origin / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000502:physiology
D004279:DNA, Viral