Jh. Sa et al., EXPRESSION OF THE ESCHERICHIA-COLI THIOREDOXIN GENE IS NEGATIVELY REGULATED BY CYCLIC-AMP, Biochemical and biophysical research communications, 234(3), 1997, pp. 564-567
Regulation of the Escherichia coli thioredoxin gene (trxA) was studied
using trxA-lac translational fusion constructed in the vector pMC1403
. Synthesis of beta-galactosidase from the trxA-lac fusion was found t
o be repressed in the presence of lactose. A switch of carbon source f
rom glucose to lactose and an addition of cyclic AMP (cAMP) caused a d
ecrease in beta-galactosidase synthesis from the trxA-lac fusion. The
repression effect of exogenous cAMP was not observed in the crp mutant
strain. The beta-galactosidase synthesis from the trxA-lac fusion lac
king a plausible cAMP-CRP binding site was not lowered in the presence
of lactose or in the addition of cAMP. Expression of the chromosomal
trxA gene was reduced by exogenous cAMP. These findings indicate that
the expression of the trxA gene is controlled by cAMP in a negative ma
nner. (C) 1997 Academic Press.