Disease relevance of lacA

• The application potentials of the expression vectors carrying the lacF marker were determined by cloning of the promoterless Escherichia coli gusA reporter gene under control of the lacA promoter followed by analysis of its expression [1].
• We have isolated mutations that appear to inactivate the gene (lacA) encoding an endogenous beta-galactosidase activity in Bacillus subtilis and in a closely linked negative regulatory element (lacR) [2].
• In addition, three defined lactococcal promoters were inserted in pNZ272: the plasmid-derived lacA promoter, the chromosomal usp45 promoter, and a promoter from bacteriophage phi SK11G [3].
• The greater similarity of the lacA and lacZ genes to homologs in gram-negative organisms than to those of gram-positive bacteria, in contrast to the homologies of the gal genes, suggests that the genes within the gal operon of L. lactis NCDO2054 have been recently acquired [4].
• Tests made on the enzymes coded by the lac operons of M5al, another Klebsiella strain (V9A) and its resident Lac plasmid, and several Lac+ Enterobacteria, led to the conclusion that only Escherichia coli among the Enterobacteria contains an active lacA gene [5].

High impact information on lacA

• Expression of both lacA and lacB was required to obtain galactose-6-phosphate isomerase activity [6].
• In particular, the structure shows similarities both overall and at the putative active site to the recently determined structure of galactoside acetyltransferase (GAT), the lacA gene product [Wang, X.-G., Olsen, L. R., and Roderick, S. L. (2002) Structure 10, 581-588] [7].
• Thus, the lacA-lacZ genes appear to have engaged the promoters of the gal operon in order to direct and control their expression [4].
• Isolation and characterization of the lacA gene encoding beta-galactosidase in Bacillus subtilis and a regulator gene, lacR [8].
• The expression vectors were equipped with the controlled and strong lacA promoter of the lactococcal lactose operon [1].

Chemical compound and disease context of lacA

• Thiogalactoside transacetylase, the product of the lacA gene of the lactose operon of Escherichia coli, has been purified by an improved procedure [9].
• We assessed the effect of insertions of the kanamycin resistance transposon Tn5 in the lac operon of Escherichia coli on the expression of distal genes lacY and lacA (melibiose fermentation at 41 degrees C and thiogalactoside transacetylase synthesis, respectively) [10].

Biological context of lacA

• The results showed that transcriptional regulation of the lac operon is mediated by the interaction between the LacR repressor, the lac promoter, and sequences in the noncoding region between the lacR and lacA genes [11].

Other interactions of lacA

• The lacA mutations may help to avoid some of the problems arising from the use of the Escherichia coli lacZ gene as a reporter gene in B. subtilis [2].

References