Open AccessExpression and regulation of the lactose transposon Tn 951 in Rhizobium spp.
Author(s) -
McGetrick Ann,
O'Regan Michael,
O'Gara Fergal
Publication year - 1985
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.1574-6968.1985.tb00829.x
Subject(s) - catabolite repression , lac operon , transposable element , biology , rhizobium , fed batch culture , escherichia coli , biochemistry , gene , genome , fermentation , mutant
The expression of β‐galactosidase by the lac transposon Tn 951 , in Escherichia coli , was found to be cAMP‐dependent. This finding provided the basis for an investigation of the effect of cAMP on Tn 951 lac expression in Rhizobium , with the ultimate aim of using the Tn 951 system as a specific probe for cAMP mediated catabolite repression. When introduced into Rhizobium , Tn 951 directed the synthesis of β‐galactosidase, which was inducible by isopropyl‐β‐ d ‐thiogalactopyranoside (IPTG). Marked quantitative and qualitative differences in β‐galactosidase expression were found between R. meliloti and R. japonicum during the growth cycle, with expression being higher in the former. β‐Galactosidase levels were, however, unaffected by exogenous cAMP under catabolite repressing conditions.