Open AccessIdentification of Cold Shock Gene Loci in Sinorhizobium meliloti by Using a luxAB Reporter Transposon
Author(s) -
Kevin P. O’Connell,
Ann Marie Gustafson,
Michael Lehmann,
Michael F. Thomashow
Publication year - 2000
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.66.1.401-405.2000
Subject(s) - biology , transposable element , gene , operon , mutant , genetics , sinorhizobium meliloti , cold shock domain , plasmid , escherichia coli , microbiology and biotechnology , insertion sequence , rna
Using aluxAB reporter transposon, seven mutants ofSinorhizobium meliloti were identified as containing insertions in four cold shock loci. LuxAB activity was strongly induced (25- to 160-fold) after a temperature shift from 30 to 15°C. The transposon and flanking host DNA from each mutant was cloned, and the nucleic acid sequence of the insertion site was determined. Unexpectedly, five of the sevenluxAB mutants contained transposon insertions in the 16S and 23S rRNA genes of two of the threerrn operons ofS. meliloti . Directed insertion ofluxAB genes into each of the threerrn operons revealed that all three operons were similarly affected by cold shock. Two other insertions were found to be located downstream of a homolog of the majorEscherichia coli cold shock gene,cspA . Although the cold shock loci were highly induced in response to a shift to low temperature, none of the insertions resulted in a statistically significant decrease in growth rate at 15°C.