ARS | Publication request: Identification of Potential Cold-Related Genes in Listeria monocytogenes

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 11, 2007
Publication Date: N/A

Technical Abstract: Listeria monocytogenes is a foodborne pathogen with the atypical ability to grow at refrigeration temperatures. One approach to identifying genes and proteins involved in growth in the cold is through creation of cold-sensitive mutants by transposon mutagenesis. L. monocytogenes strain 10403S was randomly mutagenized with transposon Tn917, and the resulting clones were scored for impaired growth at 4 degrees C. Out of a library of about 10,000 Tn917 mutagenized clones, 26 mutants were designated as cold-sensitive according to the screening criteria and were selected for further study. The mutants showed different degrees of impairment of growth at 10 degrees C. Chromosomal regions upstream and downstream of the Tn917 insertion were cloned and sequenced and the site of the transposon insertion was identified through comparison with genome sequence databases. Insertions were found in genes encoding the following putative proteins: branched-chain alpha-keto acid dehydrogenase (3 mutants), a peptidoglycan hydrolase, glutathione reductase, an ATPase, a phosphate uptake protein, phosphoenolpyruvate synthestase, competence protein ComC, transcriptional regulators (2), and ABC transporters (2). Ten insertions were in genes of unknown function and three were in intergenic regions. The results indicate that growth at low temperatures is global in its involvement of various genes and proteins, several of which have not previously been identified as having a role in growth in the cold and a significant number of which have no characterized function.