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Genome plasticity in Streptomyces : identification of 1 Mb TIRs in the S. coelicolor A3(2) chromosome
Author(s) -
Weaver David,
Karoonuthaisiri Nitsara,
Tsai HsiuHwei,
Huang ChihHung,
Ho MaiLan,
Gai Shuning,
Patel Kedar G.,
Huang Jianqiang,
Cohen Stanley N.,
Hopwood David A.,
Chen Carton W.,
Kao Camilla M.
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2003.03920.x
Subject(s) - streptomyces coelicolor , biology , genetics , chromosome , transposable element , tn10 , transposase , gene , inverted repeat , strain (injury) , genome , transposon mutagenesis , mutant , microbiology and biotechnology , anatomy
Summary 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.