Authors: Rinaldo C; Bazzicalupo P; Ederle S; Hilliard M; La Volpe A
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.
Keywords: Animals; Caenorhabditis elegans/embryology/genetics/*physiology/*radiation effects; Caenorhabditis elegans Proteins; Chromosome Aberrations/embryology/radiation effects; DNA-Binding Proteins/*physiology; Embryo, Nonmammalian/embryology/radiation effects; Gamma Rays; Meiosis/*physiology/radiation effects; RNA, Messenger/metabolism; Rad51 Recombinase; Radiation Tolerance/*genetics|
Journal: Genetics Volume: 160 Issue: 2 Pages: 471-9 Date: Feb. 28, 2002 PMID: 11861554 |
Rinaldo C, Bazzicalupo P, Ederle S, Hilliard M, La Volpe A (2002) Roles for Caenorhabditis elegans rad-51 in meiosis and in resistance to ionizing radiation during development. Genetics 160: 471-9.
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