The Arabidopsis DNA mismatch repair gene PMS1 restricts somatic recombination between homeologous sequences.
The eukaryotic DNA mismatch repair (MMR) system contributes to maintaining the fidelity of genetic information by correcting replication errors and preventing illegitimate recombination events. This study aimed to examine the function(s) of the Arabidopsis thaliana PMS1 gene (AtPMS1), one of three homologs of the bacterial MutL gene in plants. Two independent mutant alleles (Atpms1-1 and Atpms1-2) were obtained and one of these (Atpms1-1) was studied in detail. The mutant exhibited a reduction in seed set and a bias against the transmission of the mutant allele. Somatic recombination, both homologous and homeologous, was examined using a set of reporter constructs. Homologous recombination remained unchanged in the mutant while homeologous recombination was between 1.7- and 4.8-fold higher than in the wild type. This increase in homeologous recombination frequency was not correlated with the degree of sequence divergence. In RNAi lines, a range of increases in homeologous recombination were observed with two lines showing a 3.3-fold and a 3.6-fold increase. These results indicate that the AtPMS1 gene contributes to an antirecombination activity aimed at restricting recombination between diverged sequences.
Li
Liangliang
L
Département de phytologie, Université Laval, 1243 Pavillon C.-E. Marchand, 1030, avenue de la Médecine, Quebec, QC G1V 0A6, Canada.
Dion
Eric
E
Richard
Gabriel
G
Domingue
Olivier
O
Jean
Martine
M
Belzile
François J
FJ
D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D003433:Crosses, Genetic; D004260:DNA Repair / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D005298:Fertility / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005787:Gene Frequency; D005838:Genotype; D000070956:MutL Proteins; D016254:Mutagenesis, Insertional; D009154:Mutation; D030821:Plants, Genetically Modified; D034622:RNA Interference; D011995:Recombination, Genetic / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; C496208:PMS1 protein, Arabidopsis; C036483:T-DNA; D000070956:MutL Proteins