Cm. Gifford et Ss. Wallace, The genes encoding formamidopyrimidine and MutY DNA glycosylases in Escherichia coli are transcribed as part of complex operons, J BACT, 181(14), 1999, pp. 4223-4236
Escherichia coli formamidopyrimidine (Fpg) DNA glycosylase and MutY DNA gly
cosylase are base excision repair proteins that work together to protect ce
lls from the mutagenic effects of the commonly oxidized guanine product 7,8
-dihydro-8-oxoguanine. The genes encoding these proteins,fpg and mutY, are
both cotranscribed as part of complex operons.fpg is the terminal gene in a
n operon with the gene order radC, rpmB, rpmG, and fpg. This operon has tra
nscription initiation sites upstream of radC, in the radC coding region, an
d immediately upstream of fpg. There is a strong attenuator in the rpmG-fpg
intergenic region and three transcription termination sites downstream of
fpg, There is an additional site, in the radC-rpmB intergenic region, that
corresponds either to a transcription initiation site or to an RNase E or R
Nase III cleavage site, mutY is the first gene in an operon with the gene o
rder mutY,yggX mltC, and nupG. This operon has transcription initiation sit
es upstream of mutY, in the mutY coding region, and immediately upstream of
nupG. There also appear to be attenuators in the yggX-mltC and mltC-nupG i
ntergenic regions. The order of genes in these operons has been conserved o
r partially conserved only in other closely related gram-negative bacteria,
although it is not known whether the genes are cotranscribed in these othe
r organisms.