CIQUIBIC   05472
CENTRO DE INVESTIGACIONES EN QUIMICA BIOLOGICA DE CORDOBA
Unidad Ejecutora - UE
artículos
Título:
Escherichia coli frameshift mutation rate depends on the chromosomal context but not on the GATC content near the mutation site
Autor/es:
MARTINA, MA; CORREA, EME; ARGARAÑA, CE; BARRA, JL
Revista:
PLOS ONE
Editorial:
PUBLIC LIBRARY SCIENCE
Referencias:
Lugar: San Francisco; Año: 2012
ISSN:
1932-6203
Resumen:
Different
studies have suggested that mutation rate varies at different positions in the
genome. In this work we analyzed if the chromosomal
context and/or the presence of GATC sites (essential for the correct
functioning of the mismatch repair system) affect the frameshift mutation rate
in the Escherichia coli genome. We
show that in a mismatch repair deficient background, a condition where the
mutation rate reflects the fidelity of the DNA polymerization process, the
frameshift mutation rate could vary up to four times among different
chromosomal contexts. Furthermore, the mismatch repair efficiency could vary up
to eight times when compared at different chromosomal locations, indicating
that detection and/or repair of frameshift events also depends on the
chromosomal context. Also, GATC sequences have been proved to be essential for
the correct functioning of the E. coli
mismatch repair system. Using bacteriophage heteroduplexes molecules it was
shown that GATC influence the mismatch repair efficiency in a distance- and
number-dependent manner, being almost nonfunctional when GATC sequences are
located at 1 kb or more from the mutation site. Interestingly, we found that in
E. coli genomic DNA the mismatch
repair system can efficiently function even if the nearest GATC sequence is
located more than 2 kb away from the mutation site. The results presented in
this work show that even though frameshift mutations can be efficiently
generated and/or repaired anywhere in the genome, these processes can be
modulated by the chromosomal context that surrounds the mutation site.