Open AccessMolecular analysis of the dormancy response in Mycobacterium smegmatis : expression analysis of genes encoding the DevR–DevS two‐component system, Rv3134c and chaperone α‐crystallin homologues
Author(s) -
Bagchi Gargi,
Das Taposh K.,
Tyagi Jaya Sivaswami
Publication year - 2002
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2002.tb11230.x
Subject(s) - mycobacterium smegmatis , biology , mycobacterium tuberculosis , gene , devs , chaperone (clinical) , genetics , mycobacterium bovis , microbiology and biotechnology , tuberculosis , medicine , modeling and simulation , systems engineering , pathology , engineering
Mycobacteria adapt to a decrease in oxygen tension by entry into a non‐replicative persistent phase. It was shown earlier that the two‐component system, DevR–DevS, was induced in Mycobacterium tuberculosis and Mycobacterium bovis BCG cultures during hypoxia, suggesting that it may play a regulatory role in their adaptation to oxygen limitation. The presence of a homologous genetic system in Mycobacterium smegmatis was predicted by scanning its unfinished genome sequence with devR and devS genes of M. tuberculosis . Rv3134c , which is cotranscribed with devR–devS in M. tuberculosis , was also present in M. smegmatis at a similar location upstream from devR . The expression of all three genes was induced at the RNA and protein levels in M. smegmatis cultures grown under microaerobic and anaerobic conditions. The M. smegmatis genome also contained the hspX gene, encoding chaperone α‐crystallin, Acr, that was induced during hypoxia. The similarity in sequences and hypoxia‐responsive behaviour of devR–devS , Rv3134c and hspX genes in M. smegmatis and M. tuberculosis suggests that the molecular mechanisms involved in the dormancy response are likely conserved in these two species. M. smegmatis could therefore serve as a useful model for the delineation of the hypoxia response in general and DevR–DevS regulated pathways in particular.