Phenotype Image Detail

Image

Caption

Meiosis in Mcph1^tm1.2Kali/Mcph1^tm1.2Kali (BRIT1-/-) spermatocytes was arrested prior to the pachytene stage with aberrant chromosomal synapsis. The staging of spermatocytes was examined in three pairs of wild-type (WT) and mutant mice by using anti-SCP3 immunostaining of the spermatocyte nuclei spread. (A,B) No defects in mutant leptotene spermatocytes. The leptotene spermatocytes were detected in WT (A) and mutant testes (B). Scale bar, 10 um. (C,D) Aberrant bivalents in mutant zygotene spermatocytes. Compared to the WT (C) with normal synapsis initiated typically at the distal ends of the acrocentric chromosomes, many mutant bivalents showed interstitial initiation of synapsis with asynapsis on either side of the contact (D). Red arrow, sex body; yellow arrows, interstitial synapsis. (E,F) Mutant spermatocytes were prone to be fragmented prior to the pachytene stage. Unlike WT with typical pachytene morphology (E), the mutant (F) was arrested prior to the pachytene stage or zygotene/pachytene transition stage and showed fragmented chromosome (white arrows). Red arrow, sex body; yellow arrows, interstitial synapsis; Z/P represents aberrant late zygotene/pachytene transition stage; white arrows, fragmented bivalents. (G) Mutant spermatocytes were dramatically arrested prior to the pachytene stage. Three to five hundred spermatocytes at meiosis I during the first wave were counted. Data are plotted as average percentage (mean +/- SD) determined from three pairs of mutant and WT mice. *, P=/<0.01 (mutant versus WT). (H) Defective synapsis in mutant spermatocytes. Synapsis here was determined by SCP1 staining. The complete bivalents were detected at zygotene/pachytene transition in WT spermatocytes (a). However, the mutant spermatocytes exhibited incomplete, dashed-line shape bivalents in many homologs during zygotene or zygotene/pachytene transition stage (b). Green arrow represents the incomplete, dashed-line shape synapsis (bivalents). Scale bar, 10 um.

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