An SMC-like protein is required for efficient homologous recombination in Arabidopsis.
In plants, the observed low frequency of gene targeting and intrachromosomal recombination contrasts markedly with the efficient extrachromosomal recombination of DNA. Thus, chromatin accessibility can have a major influence on the recombination frequency of chromosomal DNA in vivo. An Arabidopsis mutant hypersensitive to a range of DNA-damaging treatments (UV-C, X-rays, methyl methanesulfonate and mitomycin C) is also defective in somatic intrachromosomal homologous recombination. The wild-type gene encodes a protein closely related to the structural maintenance of chromosomes (SMC) family involved in structural changes in chromosomes. Although loss of SMC function is lethal in other eukaryotes, growth of the Arabidopsis mutant is normal in the absence of genotoxic treatments. This suggests a surprisingly specialized function for this protein in plants, and provides the first in vivo evidence for the involvement of an SMC protein in recombinational DNA repair. It is possible that SMC-like proteins in plants alleviate suppressive chromatin structure limiting homologous recombination in somatic cells.
Mengiste
T
T
Friedrich Miescher Institute, PO Box 2543, CH-4002 Basel, Switzerland.
Revenkova
E
E
Bechtold
N
N
Paszkowski
J
J
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D002874:Chromosome Mapping; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D018744:DNA, Plant / Q000187:drug effects / Q000528:radiation effects; D017343:Genes, Plant; D005966:Glucuronidase / Q000235:genetics; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D016685:Mitomycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D009153:Mutagens / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic; D017386:Sequence Homology, Amino Acid; D014466:Ultraviolet Rays
D029681:Arabidopsis Proteins; D018744:DNA, Plant; C121328:MIM protein, Arabidopsis; D009153:Mutagens; D010940:Plant Proteins; D016685:Mitomycin; D008741:Methyl Methanesulfonate; D005966:Glucuronidase