title: Roles for Caenorhabditis elegans rad-51 in meiosis and in resistance to ionizing radiation during development.
abstract: We have investigated the role of Caenorhabditis elegans RAD-51 during meiotic prophase and embryogenesis, making use of the silencing effect of RNA interference (RNAi). rad-51 RNAi leads to severe defects in chromosome morphology in diakinesis oocytes. We have explored the effect of rad-51 RNAi in mutants lacking fundamental components of the recombination machinery. If double-strand breaks are prevented by spo-11 mutation, rad-51 RNAi does not affect chromosome appearance. This is consistent with a role for RAD-51 downstream of the initiation of recombination. In the absence of MRE-11, as in the absence of SPO-11, RAD-51 depletion has no effect on the chromosomes, which appear intact, thus indicating a role for MRE-11 in DSB induction. Intriguingly, rad-51 silencing in oocytes that lack MSH-5 leads to chromosome fragmentation, a novel trait that is distinct from that seen in msh-5 mutants and in rad-51 RNAi oocytes, suggesting new potential roles for the msh-5 gene. Silencing of the rad-51 gene also causes a reduction in fecundity, which is suppressed by mutation in the DNA damage checkpoint gene rad-5, but not in the cell death effector gene ced-3. Finally, RAD-51 depletion is also seen to affect the soma, resulting in hypersensitivity to ionizing radiation in late embryogenesis.
authors.affiliation: Istituto di Genetica e Biofisica Adriano Buzzati-Traverso-CNR, 80125 Naples, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Rinaldo
authors.forename: Paolo
authors.initials: P
authors.lastname: Bazzicalupo
authors.forename: Sara
authors.initials: S
authors.lastname: Ederle
authors.forename: Massimo
authors.initials: M
authors.lastname: Hilliard
authors.forename: Adriana
authors.initials: A
authors.lastname: La Volpe
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects*; D029742:Caenorhabditis elegans Proteins; D002869:Chromosome Aberrations / Q000196:embryology / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000528:radiation effects; D005720:Gamma Rays; D008540:Meiosis / Q000502:physiology* / Q000528:radiation effects; D012333:RNA, Messenger / Q000378:metabolism; D051135:Rad51 Recombinase; D011836:Radiation Tolerance / Q000235:genetics*
chemical_list: D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D051135:Rad51 Recombinase; C495148:rad-51 protein, C elegans