Two chimeric chromosomes of Streptomyces coelicolor A3(2) generated by single crossover of the wild-type chromosome and linear plasmid scp1.
Streptomyces coelicolor A3(2) strain 2106 carries a 1.85-Mb linear plasmid, SCP1'-cysD, in addition to a 7.2-Mb linear chromosome. Macrorestriction analysis indicated that both linear DNAs are hybrids of the wild-type chromosome and the linear plasmid SCP1 on each side. Nucleotide sequencing of the fusion junctions revealed no homology between the recombination regions. SCP1'-cysD contains an SCP1 telomere and a chromosomal telomere at each end and therefore does not have terminal inverted repeats. In addition, SCP1'-cysD could not be eliminated from strain 2106 by various mutagenic treatments. Thus, we concluded that both the 7.2-Mb chromosome and SCP1'-cysD are chimeric chromosomes generated by a single crossover of the wild-type chromosome and SCP1. This may be regarded as a model of chromosomal duplication in genome evolution.
Yamasaki
Masayuki
M
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan.
Kinashi
Haruyasu
H
D000595:Amino Acid Sequence; D001483:Base Sequence; D002678:Chimera; D002876:Chromosomes, Bacterial; D008969:Molecular Sequence Data; D010957:Plasmids; D013302:Streptomyces / Q000235:genetics*; D016615:Telomere; D020079:Terminal Repeat Sequences