CEP250 is Required for Maintaining Centrosome Cohesion in the Germline and Fertility in Male Mice

Abstract

Male gametogenesis involves both mitotic divisions to amplify germ cell progenitors that gradually differentiate and meiotic divisions. Centrosomal regulation is essential for both types of divisions, with centrioles remaining tightly paired during the interphase. Here, we generated and characterized the phenotype of mutant mice devoid of Cep250/C-Nap1, a gene encoding for a docking protein for fibers linking centrioles, and characterized their phenotype. The Cep250-/- mice presented with no major defects, apart from male infertility due to a reduction in the spermatogonial pool and the meiotic blockade. Spermatogonial stem cells expressing Zbtb16 were not affected, whereas the differentiating spermatogonia were vastly lost. These cells displayed abnormal γH2AX-staining, accompanied by an increase in the apoptotic rate. The few germ cells that survived at this stage, entered the meiotic prophase I and were arrested at a pachytene-like stage, likely due to synapsis defects and the unrepaired DNA double-strand breaks. In these cells, centrosomes split up precociously, with γ-tubulin foci being separated whereas these were closely associated in wild-type cells. Interestingly, this lack of cohesion was also observed in wild-type female meiocytes, likely explaining the normal fertility of Cep250-/- female mice. Taken together, this study proposes a specific requirement of centrosome cohesion in the male germline, with a crucial role of CEP250 in both differentiating spermatogonia and meiotic spermatocytes.

Emerging roles of centrosome cohesion

“…The Seckel-like syndrome phenotype of cattle with a homozygous truncation mutation in CEP250 made it important to study the consequence of CEP250 knockout in a mammalian model organism such as mouse. Two recent studies reported phenotypes of Cep250 KO mice [ 95 , 96 ]. Dang et al .…”

“…[ 95 ] used Cep250 KO mice from gene deletion by Cre/LoxP system, while Floriot et al . [ 96 ] generated Cep250 KO by the transcription activator-like effector nuclease TALEN. In both cases, the targeted mutations resulted in changes in first few exons of the CEP250 gene, resulting in premature stop codons and short non-functional N-terminal C-Nap1 fragments, which do not localize to the centrosome [ 95 , 96 ].…”

“…[ 96 ] generated Cep250 KO by the transcription activator-like effector nuclease TALEN. In both cases, the targeted mutations resulted in changes in first few exons of the CEP250 gene, resulting in premature stop codons and short non-functional N-terminal C-Nap1 fragments, which do not localize to the centrosome [ 95 , 96 ]. Importantly, both manuscripts report that Cep250 KO mice have defects in centrosome cohesion in the germline and male gametogenesis [ 95 , 96 ].…”

“…In both cases, the targeted mutations resulted in changes in first few exons of the CEP250 gene, resulting in premature stop codons and short non-functional N-terminal C-Nap1 fragments, which do not localize to the centrosome [ 95 , 96 ]. Importantly, both manuscripts report that Cep250 KO mice have defects in centrosome cohesion in the germline and male gametogenesis [ 95 , 96 ]. However, the MT centrosome cohesion pathway is still functional in Cep250 KO MEFs as indicated by an increase in centrosome disjunction by the addition of the MT depolymerizing drug nocodazole.…”

“…Floriot et al . [ 96 ] identified an additional function of CEP250 in male meiosis. Cep250 KO spermatocytes show abnormal meiotic progression as they are unable to progress through meiosis I [ 95 , 96 ].…”