OTOGL, a gelforming mucin protein, is nonessential for male germ cell development and spermatogenesis in mice

The paralogs' enigma of germ-cell specific genes dispensable for fertility: the case of 19 oogenesin genes†

Gene knockout experiments have shown that many genes are dispensable for a given biological function. In this review, we make an assessment of male and female germ cell-specific genes dispensable for the function of reproduction in mice, the inactivation of which does not affect fertility. In particular, we describe the deletion of a 1 Mb block containing nineteen paralogous genes of the oogenesin/Pramel family specifically expressed in female and/or male germ cells, which has no consequences in both sexes. We discuss this notion of dispensability and the experiments that need to be carried out to definitively conclude that a gene is dispensable for a function.

ADAD2 interacts with RNF17 in P-bodies to repress the Ping-pong cycle in pachytene piRNA biogenesis

Pachytene piRNA biogenesis is a hallmark of the germline, distinct from another wave of pre-pachytene piRNA biogenesis with regard to the lack of a secondary amplification process known as the Ping-pong cycle. However, the underlying molecular mechanism and the venue for the suppression of the Ping-pong cycle remain elusive. Here, we showed that a testis-specific protein, ADAD2, interacts with a TDRD family member protein RNF17 and is associated with P-bodies. Importantly, ADAD2 directs RNF17 to repress Ping-pong activity in pachytene piRNA biogenesis. The P-body localization of RNF17 requires the intrinsically disordered domain of ADAD2. Deletion of Adad2 or Rnf17 causes the mislocalization of each other and subsequent Ping-pong activity derepression, secondary piRNAs overproduced, and disruption of P-body integrity at the meiotic stage, thereby leading to spermatogenesis arrested at the round spermatid stage. Collectively, by identifying the ADAD2-dependent mechanism, our study reveals a novel function of P-bodies in suppressing Ping-pong activity in pachytene piRNA biogenesis.

SERBP1 Promotes Stress Granule Clearance by Regulating 26S Proteasome Activity and G3BP1 Ubiquitination and Protects Male Germ Cells from Thermostimuli Damage

Stress granules (SGs) are membraneless cytoplasmic condensates that dynamically assemble in response to various stressors and reversibly disassemble after stimulus removal; however, the mechanisms underlying SG dynamics and their physiological roles in germ cell development are elusive. Here, we show that SERBP1 (SERPINE1 mRNA binding protein 1) is a universal SG component and conserved regulator of SG clearance in somatic and male germ cells. SERBP1 interacts with the SG core component G3BP1 and 26S proteasome proteins PSMD10 and PSMA3 and recruits them to SGs. In the absence of SERBP1, reduced 20S proteasome activity, mislocalized valosin containing protein (VCP) and Fas associated factor family member 2 (FAF2), and diminished K63-linked polyubiquitination of G3BP1 during the SG recovery period were observed. Interestingly, the depletion of SERBP1 in testicular cells in vivo causes increased germ cell apoptosis upon scrotal heat stress. Accordingly, we propose that a SERBP1-mediated mechanism regulates 26S proteasome activity and G3BP1 ubiquitination to facilitate SG clearance in both somatic and germ cell lines.