Multiple transcription factors regulate the expression of genes for
error prone DNA polymerases in Acinetobacter baumannii
Abstract
Acinetobacter baumannii is an opportunistic pathogen causing
several infections that are increasingly difficult to treat due to its
ability to rapidly gain antibiotic resistances. These resistances can
arise due to mutations during the DNA damage response (DDR), through the
activity of error-prone DNA polymerases, such as DNA polymerase V (DNA
Pol V). Currently, the DDR in A. baumannii is not well understood
and the regulation of genes encoding multiple copies of DNA Pol V is not
fully characterized. Through genome wide mutagenesis, we have identified
a novel TetR-like family regulator of genes that encode DNA Pol V, which
we have named E rror- p rone p olymerase r egulator, EppR. We
have found that EppR represses the expression of the genes encoding DNA
Pol V and itself through direct binding to a conserved EppR motif in
their promoters. Lastly, we show that EppR also regulates UmuDAb,
previously identified as a regulator of genes encoding DNA Pol V. These
two gene products are functionally required to ensure regulation of
expression of genes encoding DNA Pol Vs and umuDAb. With these
results, we propose a co-repressor model for the regulation of genes
encoding DNA Pol V and umuDAb.