Genome plasticity in Streptomyces: identification of 1 Mb TIRs in the S. coelicolor A3(2) chromosome.
The chromosomes of several widely used laboratory derivatives of Streptomyces coelicolor A3(2) were found to have 1.06 Mb inverted repeat sequences at their termini (i.e. long-terminal inverted repeats; L-TIRs), which are 50 times the length of the 22 kb TIRs of the sequenced S. coelicolor strain M145. The L-TIRs include 1005 annotated genes and increase the overall chromosome size to 9.7 Mb. The 1.06 Mb L-TIRs are the longest reported thus far for an actinomycete, and are proposed to represent the chromosomal state of the original soil isolate of S. coelicolor A3(2). S. coelicolor A3(2), M600 and J1501 possess L-TIRs, whereas approximately half the examined early mutants of A3(2) generated by ultraviolet (UV) or X-ray mutagenesis have truncated their TIRs to the 22 kb length. UV radiation was found to stimulate L-TIR truncation. Two copies of a transposase gene (SCO0020) flank 1.04 Mb of DNA in the right L-TIR, and recombination between them appears to generate strains containing short TIRs. This TIR reduction mechanism may represent a general strategy by which transposable elements can modulate the structure of chromosome ends. The presence of L-TIRs in certain S. coelicolor strains represents a major chromosomal alteration in strains previously thought to be genetically similar.
Department of Chemical Engineering, MC 5025, Stanford University, Stanford, CA 94305, USA.
David
D
Weaver
Nitsara
N
Karoonuthaisiri
Hsiu-Hwei
HH
Tsai
Chih-Hung
CH
Huang
Mai-Lan
ML
Ho
Shuning
S
Gai
Kedar G
KG
Patel
Jianqiang
J
Huang
Stanley N
SN
Cohen
David A
DA
Hopwood
Carton W
CW
Chen
Camilla M
CM
Kao
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping / Q000379:methods; D002876:Chromosomes, Bacterial / Q000235:genetics*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry* / Q000302:isolation & purification; D016521:Electrophoresis, Gel, Pulsed-Field; D005798:Genes, Bacterial / Q000235:genetics; D016680:Genome, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012329:RNA, Bacterial / Q000737:chemistry* / Q000302:isolation & purification; D011995:Recombination, Genetic / Q000235:genetics; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000235:genetics; D020079:Terminal Repeat Sequences / Q000235:genetics; D019895:Transposases / Q000235:genetics / Q000378:metabolism
D004269:DNA, Bacterial; D012329:RNA, Bacterial; D019895:Transposases