A Potential Role for the Gsdf-eEF1α Complex in Inhibiting Germ Cell Proliferation: A Protein-Interaction Analysis in Medaka (Oryzias latipes) From a Proteomics Perspective

Gonadal soma-derived factor (gsdf) has been demonstrated to be essential for testicular differentiation in medaka (Oryzias latipes). To understand the protein dynamics of Gsdf in spermatogenesis regulation, we used a His-tag pull-down assay coupled with shotgun LC-MS/ MS to identify a group of potential interacting partners for Gsdf, which included cytoplasmic dynein light chain 2, eukaryotic polypeptide elongation factor 1 alpha (eEF1 alpha), and actin filaments in the mature medaka testis. As for the interaction with transforming growth factor beta-dynein being critical for spermatogonial division in Drosophila melanogaster, the physical interactions of Gsdf-dynein and Gsdf-eEF1 alpha were identified through a yeast 2-hybrid screening of an adult testis cDNA library using Gsdf as bait, which were verified by a paired yeast 2-hybrid assay. Coimmunoprecipitation of Gsdf and eEF1 alpha was defined in adult testes as supporting the requirement of a Gsdf and eEF1 alpha interaction in testis development. Proteomics analysis (data are available via ProteomeXchange with identifier PXD022153) and ultrastructural observations showed that Gsdf deficiency activated eEF1 alpha-mediated protein synthesis and ribosomal biogenesis, which in turn led to the differentiation of undifferentiated germ cells. Thus, our results provide a framework and new insight into the coordination of a Gsdf (transforming growth factor beta) and eEF1 alpha complex in the basic processes of germ cell proliferation, transcriptional and translational control of sexual RNA, which may be fundamentally conserved across the phyla during sexual differentiation.

Automated summary

Gsdf interacts with various proteins, promoting protein synthesis and ribosomal biogenesis to drive the differentiation of undifferentiated germ cells. This interaction plays a crucial role in the basic processes of germ cell proliferation, transcriptional and translational control of sexual RNA, potentially conserved across different species during sexual differentiation.