RNA interference inhibition of Mus81 reduces mitotic recombination in human cells.
Mus81 is a highly conserved endonuclease with homology to the XPF subunit of the XPF-ERCC1 complex. In yeast Mus81 associates with a second subunit, Eme1 or Mms4, which is essential for endonuclease activity in vitro and for in vivo function. Human Mus81 binds to a homolog of fission yeast Eme1 in vitro and in vivo. We show that recombinant Mus81-Eme1 cleaves replication forks, 3' flap substrates, and Holliday junctions in vitro. By use of differentially tagged versions of Mus81 and Eme1, we find that Mus81 associates with Mus81 and that Eme1 associates with Eme1. Thus, complexes containing two or more Mus81-Eme1 units could function to coordinate substrate cleavage in vivo. Down-regulation of Mus81 by RNA interference reduces mitotic recombination in human somatic cells. The recombination defect is rescued by expression of a bacterial Holliday junction resolvase. These data provide direct evidence for a role of Mus81-Eme1 in mitotic recombination in higher eukaryotes and support the hypothesis that Mus81-Eme1 resolves Holliday junctions in vivo.
Blais
Veronique
V
Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
Gao
Hui
H
Elwell
Cherilyn A
CA
Boddy
Michael N
MN
Gaillard
Pierre-Henri L
PHL
Russell
Paul
P
McGowan
Clare H
CH
D000595:Amino Acid Sequence; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism; D002470:Cell Survival / Q000502:physiology; D003001:Cloning, Molecular; D004249:DNA Damage / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004720:Endonucleases / Q000235:genetics* / Q000378:metabolism*; D006367:HeLa Cells; D045565:Holliday Junction Resolvases / Q000378:metabolism; D006801:Humans; D008938:Mitosis / Q000235:genetics*; D008969:Molecular Sequence Data; D011485:Protein Binding; D034622:RNA Interference; D011995:Recombination, Genetic / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C442837:Eme1 protein, S pombe; D004720:Endonucleases; C411624:MUS81 protein, S cerevisiae; C498772:MUS81 protein, human; D045565:Holliday Junction Resolvases