Ankrd7, a novel gene specifically expressed in Sertoli cells and its potential roles in Sertoli cell maturation

CRISPR/Cas9-mediated genome editing reveals 30 testis-enriched genes dispensable for male fertility in mice†

More than 1000 genes are predicted to be predominantly expressed in mouse testis, yet many of them remain unstudied in terms of their roles in spermatogenesis and sperm function and their essentiality in male reproduction. Since individually indispensable factors can provide important implications for the diagnosis of genetically related idiopathic male infertility and may serve as candidate targets for the development of nonhormonal male contraceptives, our laboratories continuously analyze the functions of testis-enriched genes in vivo by generating knockout mouse lines using the CRISPR/Cas9 system. The dispensability of genes in male reproduction is easily determined by examining the fecundity of knockout males. During our large-scale screening of essential factors, we knocked out 30 genes that have a strong bias of expression in the testis and are mostly conserved in mammalian species including human. Fertility tests reveal that the mutant males exhibited normal fecundity, suggesting these genes are individually dispensable for male reproduction. Since such functionally redundant genes are of diminished biological and clinical significance, we believe that it is crucial to disseminate this list of genes, along with their phenotypic information, to the scientific community to avoid unnecessary expenditure of time and research funds and duplication of efforts by other laboratories.

Eukaryotic protein recruitment into the Chlamydia inclusion: implications for survival and growth

Chlamydia trachomatis (Ct) is an obligate intracellular human pathogen that multiplies within a parasitophorous vacuole called an inclusion. We report that the location of several host-cell proteins present in the cytosol, the nucleus, and membranes was altered during Ct development. The acyl-CoA synthetase enzyme ACSL3 and the soluble acyl-CoA binding protein ACBD6 were mobilized from organelle membranes and the nucleus, respectively, into the lumen of the inclusion. The nuclear protein ZNF23, a pro-apoptosis factor, was also translocated into the inclusion lumen. ZNF23, among other proteins, might be targeted by Ct to inhibit host cell apoptosis, thereby enabling bacterial survival. In contrast, the acyl-CoA:lysophosphatidylcholine acyltransferase LPCAT1, an endoplasmic reticulum membrane protein, was recruited to the inclusion membrane. The coordinated action of ACBD6, ACSL3 and LPCAT1 likely supports remodeling and scavenging of host lipids into bacterial-specific moieties essential to Ct growth. To our knowledge, these are the first identified host proteins known to be intercepted and translocated into the inclusion.

Localization of ubiquitin specific protease 26 at blood-testis barrier and near Sertoli cell-germ cell interface in mouse testes

Ubiquitin Specific Protease 26 (USP26) is a little studied ubiquitin-specific protease that is expressed specifically in the testis. In humans, some USP26 polymorphisms have been reported to be associated with impaired male fertility. However, how USP26 affects male reproduction remains unclear. We generated an antibody that stained specifically cultured cells expressing an epitope-tagged USP26 and used it to elucidate the biological function of USP26. Immunostaining of mouse testis sections as well as dispersed germ cells showed the presence of USP26 at the blood-testis barrier, near the Sertoli cell-germ cell interface of post-step 7 spermatids, and coating the dorsal surface of sperm head. Further RT-PCR assays detected the expression of Usp26 in germ cells, but not in primary Sertoli cell lines. In addition, USP26 immunoprecipitated from testis lysates exhibited deubiquitinating activities. The localization of USP26 in the testis suggests a possible role in the movement of germ cells along the seminiferous epithelium.