EH domain binding protein 1-like 1 (EHBP1L1), a protein with calponin homology domain, is expressed in the rat testis

In this paper, with the aim to find new genes involved in mammalian spermatogenesis, we isolated, for the first time in the rat testis, a partial cDNA clone encoding for EH domain binding protein 1-like 1 (Ehbp1l1), a protein that has a single Calponin homology domain (CH). Bioinformatic analysis showed that EHBP1l1 contains three domains: the N-terminal C2-like, the CH and the C-terminal bivalent Mical/EHBP Rab binding (bMERB) domains, which are evolutionary conserved in the vertebrates. We found that Ehbp1l1 mRNA is expressed in several rat tissue, including liver, intestine, kidney and also in the testis during its development, with a higher level in 12-month-old testis. Interestingly, in situ hybridization experiments revealed that Ehbp1l1 is specifically expressed by I and II spermatocytes, result validated by the RT-PCR performed on total RNA obtained from enriched fraction of different testicular cell types. Since EHBP1l1 have been described to link vesicular transport to the actin cytoskeleton, being an effector of the small GTPase Rab8, we hypothesize that it could participate both in cytoskeletal remodeling and in the regulation of vesicle sorting from the Trans-Golgi Network to the apical plasma membrane. Our findings provide a better understand of the molecular mechanisms of the differentiation process of spermatogenesis and Ehbp1l1 may also be used as a new marker of testicular activity.