Genetic and transcriptional organization of the groEL operon containing trxA in Gemella morbillorum.
Gemella morbillorum, a low G+C content Gram-positive bacterium, is considered to be a commensal organism in humans but occasionally causes endocarditis or other diseases. We determined the sequences of groESL, dnaK and their flanking regions in G. morbillorum. Sequence analysis revealed the presence of putative CtsR binding sites in both groE and dnaK operons, but the lack of CIRCE in groE and the presence of CIRCE in dnaK. This finding suggests in addition to the known regulatory systems for the class I heat shock protein genes, there may be another model in G. morbillorum. Furthermore, an unusual organization of the groE operon as groES-groEL-trxA was found. Genome sequence on GenBank database and southern blot indicate that there is only one copy of trxA in G. morbillorum. Sequencing of the groE locus from other Gemella species and clinical isolates revealed the same genetic structure, suggesting the conservation of the structure in Gemella species. Northern hybridization revealed that there were two transcripts, a large transcript, groES-groEL-trxA and a small transcript, trxA, in groE operon. Treatment of heat or diamide increased the transcription level of groES-groEL-trxA, whereas these two stresses did not affect the small trxA transcript. Thus, this study reveals that the trxA is co-transcribed with the groE operon, and most possibly under the control of the CtsR.
Department of Clinical Laboratory Sciences, National Taiwan University, College of Medicine, Taiwan. b88404030@ntu.edu.tw
Wei-Chun
WC
Hung
Hsiao-Jan
HJ
Chen
Sung-Pin
SP
Tseng
Shwu-Jen
SJ
Liaw
Jui-Chang
JC
Tsai
Po-Ren
PR
Hsueh
Lee-Jene
LJ
Teng
D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D018835:Chaperonin 10 / Q000235:genetics; D018834:Chaperonin 60 / Q000235:genetics*; D018833:Chaperonins / Q000235:genetics; D002875:Chromosomes / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D058834:Gemella / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D005798:Genes, Bacterial; D056426:Genetic Loci / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009876:Operon; D017421:Sequence Analysis / Q000379:methods; D014158:Transcription, Genetic / Q000235:genetics*
D001426:Bacterial Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; D004269:DNA, Bacterial; C097970:GroESL protein, Bacteria; D006360:Heat-Shock Proteins; D018833:Chaperonins