A 189-bp repeat region within the human cytomegalovirus replication origin contains a sequence dispensable but irreplaceable with other sequences.
The human cytomegalovirus (HCMV) replication origin exhibits a strain-dependent difference in the number of copies of a 189-bp region: the AD169 and Towne strains contain one and three copies of the region, respectively. A nearly complete deletion of the 189-bp repeat region of the Towne strain does not eliminate the origin's ability to initiate DNA synthesis. Here we report that the replication ability of the HCMV replication origin in infected cells disappeared after replacements of an internal sequence (152 bp) of the 189-bp repeat region with lambda DNA of identical and different lengths as well as after introduction of multiple nucleotide substitutions within the 152-bp internal sequence of the 189-bp repeat. In contrast, a variation in the copy number of 189-bp region (either one or two copies) or an inversion of the 152-bp internal sequence of the 189-bp repeat maintained replication abilities similar to those of the wild-type origin of the Towne strain. These results indicate that the 189-bp repeat region within the HCMV replication origin is not just a dispensable spacer sequence but instead contains an irreplaceable sequence that may play a supporting role in HCMV DNA replication.
Chen
Z
Z
The Institute of Medical Science, The University of Tokyo, Tokyo, 108, Japan.
Sugano
S
S
Watanabe
S
S
D019943:Amino Acid Substitution; D002460:Cell Line; D007446:Chromosome Inversion; D003587:Cytomegalovirus / Q000235:genetics*; D004279:DNA, Viral; D018628:Gene Dosage; D014644:Genetic Variation; D006801:Humans; D016296:Mutagenesis; D012091:Repetitive Sequences, Nucleic Acid; D018741:Replication Origin
D004279:DNA, Viral