Mouse strains with an active H2-Ea meiotic recombination hot spot exhibit increased levels of H2-Ea-specific DNA breaks in testicular germ cells.
We devised a sensitive method for the site-specific detection of rare meiotic DNA strand breaks in germ cell-enriched testicular cell populations from mice that possess or lack an active recombination hot spot at the H2-Ea gene. Using germ cells from adult animals, we found an excellent correlation between the frequency of DNA breaks in the 418-bp H2-Ea hot spot and crossover activity. The temporal appearance of DNA breaks was also studied in 7- to 18-day-old mice with an active hot spot during the first waves of spermatogenesis. The number of DNA breaks detected rose as leptotene and zygotene spermatocytes populate the testis with a peak at day 14 postpartum, when leptotene, zygotene, and early pachytene spermatocytes are the most common meiotic prophase I cell types. The number of DNA breaks drops precipitously 1 day later, when middle to late pachytene spermatocytes become the dominant subtype. The recombination-related breaks in the hot spot likely reflect SPO11-induced double-strand breaks and/or recombination intermediates containing free 3' hydroxyl groups.
Qin
Jian
J
Program in Molecular and Computational Biology, University of Southern California, Los Angeles, California 90089-1340, USA.
Richardson
Laura L
LL
Jasin
Maria
M
Handel
Mary Ann
MA
Arnheim
Norman
N
D000818:Animals; D001483:Base Sequence; D004249:DNA Damage / Q000235:genetics*; D005260:Female; D005854:Germ Cells / Q000378:metabolism*; D006183:H-2 Antigens / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics; D006579:Heterozygote; D008297:Male; D008540:Meiosis / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D011995:Recombination, Genetic / Q000235:genetics*; D013737:Testis / Q000166:cytology* / Q000378:metabolism
D006183:H-2 Antigens