Phenotype Image Detail

Image

Caption

Recombination DNA repair was impaired in Mcph1^tm1.2Kali/Mcph1^tm1.2Kali (BRIT1-/-) spermatocytes. Wild-type (WT) and mutant spermatocytes were obtained from P17.5-P22.5 mice, and subjected for chromosome spreading and then double-stained immunofluorescently with anti-SCP3/anti-SPO11, anti-SCP3/anti-gamma-H2AX, anti-SCP3/anti-RAD51, or anti-SCP3/anti-BRCA2 antibodies, respectively. Anti-SCP3 staining was used to determine the stage of each spermatocyte. Total around 400 chromosome spreads from three sets of mice were analyzed. Scale bar, 10 um. (A) DNA double-strand breaks (DSBs) formation in meiosis is not affected by loss of Brit1. SPO11 foci had the similar pattern in WT and BRIT1-deficient spermatocytes. (B) Gamma-H2AX foci formation at leptotene/zygotene was comparable between WT and mutant spermatocytes. Both WT (a) and mutant (b) spermatocytes exhibited abundant gamma-H2AX foci in response to DSBs at leptotene/zygotene stages, although gamma-H2AX foci disappeared at the late zygotene/pachytene stage except in the XY body in WT (c), and they were sustained on asynapsed autosomal homologs in the mutant spermatocytes at late zygotene (d). (C) Retained gamma-H2AX foci during late zygotene spermatocyte in BRIT1-deficient spermatocytes. Value shown here represents the mean +/- SD from ~50 late zygotene spermatocytes for each genotype. (D) RAD51 foci were dramatically decreased in zygotene stage of mutant spermatocytes. RAD51 foci were formed intensively on zygotene homologs in WT (a) while few foci were detected in the mutant zygotene (b). (E) Remarkable reduction in the number of RAD51 foci per leptotene/zygotene spermatocyte in mutant spermatocytes. Value shown here represents the mean +/- SD from ~50 leptotene/zygotene spermatocytes for each genotype. (F) BRCA2 foci formation was disrupted in mutant spermatocytes. BRCA2 foci were formed intensively on bivalents at zygotene in WT (a) but not in the mutant zygotene (b). (G) Substantial reduction in the number of BRCA2 foci per leptotene/zygotene spermatocyte in mutant spermatocytes. Value shown here represents the mean +/- SD from ~50 leptotene/zygotene spermatocytes for each genotype.

Copyright

This image is from Liang Y, PLoS Genet 2010 Jan;6(1):e1000826, and is displayed under the terms of the Creative Commons Attribution 4.0 International License. J:156371

Associated Alleles

Symbol	Name
Mcph1^tm1.2Kali	microcephaly, primary autosomal recessive 1; targeted mutation 1.2, Kaiyi Li

Associated Genotypes

Allelic Composition	Genetic Background
Mcph1^tm1.2Kali/Mcph1^tm1.2Kali	involves: 129S7/SvEvBrd * C57BL/6J