Expression of malT, the regulator gene of the maltose region in Escherichia coli, is limited both at transcription and translation
Chapon, C.
EMBO Journal 1(3): 369-374
1982
ISSN/ISBN: 0261-4189 PMID: 6325162 Document Number: 189491
Six mutations in E. coli, which lead to an increase in malT expression, were mapped by sequencing techniques. All of them had one or another of 2 base changes. Determination of the transcription start point by reverse transcriptase mapping localized the 2 base changes with respect to the elements that control malT expression. One of the base changes (malTp1) is located in the Pribnow box of the promoter, and presumably results in an increase in the rate of transcription initiation. The other (malTp7) is located in the Shine and Dalgarno sequence, which precedes the malT cistron. It probably created a more favorable ribosome binding site on malT mRNA. A correlate of these observations is that the promoter and the ribosome binding site are both inefficient in a wild-type malT gene. A malTp1 malTp7 double mutants was constructed, which produced .apprx. 30 times more MalT protein than the wild-type strain.