title: DNA polymerase beta is critical for mouse meiotic synapsis.
abstract: We have shown earlier that DNA polymerase beta (Pol beta) localizes to the synaptonemal complex (SC) during Prophase I of meiosis in mice. Pol beta localizes to synapsed axes during zygonema and pachynema, and it associates with the ends of bivalents during late pachynema and diplonema. To test whether these localization patterns reflect a function for Pol beta in recombination and/or synapsis, we used conditional gene targeting to delete the PolB gene from germ cells. We find that Pol beta-deficient spermatocytes are defective in meiotic chromosome synapsis and undergo apoptosis during Prophase I. We also find that SPO11-dependent gammaH2AX persists on meiotic chromatin, indicating that Pol beta is critical for the repair of SPO11-induced double-strand breaks (DSBs). Pol beta-deficient spermatocytes yielded reduced steady-state levels of the SPO11-oligonucleotide complexes that are formed when SPO11 is removed from the ends of DSBs, and cytological experiments revealed that chromosome-associated foci of replication protein A (RPA), RAD51 and DMC1 are less abundant in Pol beta-deficient spermatocyte nuclei. Localization of Pol beta to meiotic chromosomes requires the formation of SPO11-dependent DSBs. Taken together, these findings strongly indicate that Pol beta is required at a very early step in the processing of meiotic DSBs, at or before the removal of SPO11 from DSB ends and the generation of the 3' single-stranded tails necessary for subsequent strand exchange. The chromosome synapsis defects and Prophase I apoptosis of Pol beta-deficient spermatocytes are likely a direct consequence of these recombination defects.
authors.affiliation: Department of Therapeutic Radiology, The Yale Comprehensive Cancer Center, New Haven, CT, USA.
authors.forename: Dawit
authors.initials: D
authors.lastname: Kidane
authors.forename: Alan S
authors.initials: AS
authors.lastname: Jonason
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Gorton
authors.forename: Ivailo
authors.initials: I
authors.lastname: Mihaylov
authors.forename: Jing
authors.initials: J
authors.lastname: Pan
authors.forename: Scott
authors.initials: S
authors.lastname: Keeney
authors.forename: Dirk G
authors.initials: DG
authors.lastname: de Rooij
authors.forename: Terry
authors.initials: T
authors.lastname: Ashley
authors.forename: Agnes
authors.initials: A
authors.lastname: Keh
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Liu
authors.forename: Urmi
authors.initials: U
authors.lastname: Banerjee
authors.forename: Daniel
authors.initials: D
authors.lastname: Zelterman
authors.forename: Joann B
authors.initials: JB
authors.lastname: Sweasy
mesh_terms: D000818:Animals; D023902:Chromosome Pairing; D002875:Chromosomes / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D019951:DNA Polymerase beta / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair; D004706:Endodeoxyribonucleases; D004950:Esterases / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D008297:Male; D008540:Meiosis; D051379:Mice / Q000378:metabolism*; D012671:Seminiferous Tubules / Q000166:cytology / Q000648:ultrastructure; D013090:Spermatocytes / Q000201:enzymology*; D000099257:Meiotic Recombination Protein SPO11
chemical_list: D019951:DNA Polymerase beta; D004706:Endodeoxyribonucleases; D004950:Esterases; D000099257:Meiotic Recombination Protein SPO11