Mammalian meiosis involves DNA double-strand breaks with 3' overhangs.
Meiotic recombination in yeast is initiated at DNA double-strand breaks (DSBs), processed into 3' single-strand overhangs that are active in homology search, repair and formation of recombinant molecules. Are 3' overhangs recombination intermediaries in mouse germ cells too? To answer this question we developed a novel approach based on the properties of the Klenow enzyme. We carried out two different, successive in situ Klenow enzyme-based reactions on sectioned preparations of testicular tubules. Signals showing 3' overhangs were observed during wild-type mouse spermatogenesis, but not in Spo11(-/-) males, which lack meiotic DSBs. In Atm(-/-) mice, abundant positively stained spermatocytes were present, indicating an accumulation of non-repaired DSBs, suggesting the involvement of ATM in repair of meiotic DSBs. Thus the processing of DSBs into 3' overhangs is common to meiotic cells in mammals and yeast, and probably in all eukaryotes.
Zenvirth
Drora
D
Department of Genetics, The Hebrew University, Jerusalem 91904, Israel.
Richler
Carmelit
C
Bardhan
Amit
A
Baudat
Frédéric
F
Barzilai
Ari
A
Wahrman
Jacob
J
Simchen
Giora
G
D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D004260:DNA Repair; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004950:Esterases / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D008297:Male; D008540:Meiosis; D051379:Mice; D018345:Mice, Knockout; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013090:Spermatocytes / Q000166:cytology / Q000378:metabolism; D013091:Spermatogenesis; D025521:Tumor Suppressor Proteins; D000099257:Meiotic Recombination Protein SPO11
D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D004247:DNA; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004950:Esterases; D017346:Protein Serine-Threonine Kinases; D025521:Tumor Suppressor Proteins; D000099257:Meiotic Recombination Protein SPO11; C576325:Atm protein, mouse