Spermatogenesis is a highly specialized process of cellular differentiation to produce spermatozoa. This differentiation process accompanies morphological changes that are controlled by a number of genes expressed in a stage-specific manner during spermatogenesis. Here we show that in mice, the absence of a testis-specific, cytoplasmic polyadenylate [poly(A)] polymerase, TPAP, results in the arrest of spermiogenesis. TPAP-deficient mice display impaired expression of haploid-specific genes that are required for the morphogenesis of germ cells. The TPAP deficiency also causes incomplete elongation of poly(A) tails of particular transcription factor messenger RNAs. Although the overall cellular level of the transcription factor TAF10 is unaffected, TAF10 is insufficiently transported into the nucleus of germ cells. We propose that TPAP governs germ cell morphogenesis by modulating specific transcription factors at posttranscriptional and posttranslational levels.
We have identified cDNA and genomic clones encoding a homologue of pancreatic trypsin, termed TESP4, as a candidate protein involved in the sperm penetration of the egg zona pellucida in mouse. The deduced amino acid sequence indicates that TESP4 is 90% identical to pancreatic trypsin. Analysis of Northern blotting and reverse transcriptase-polymerase chain reaction reveals that the mouse TESP4 gene is ubiquitously expressed in all tissues tested, including the pancreas and testis, and the transcript is present in the haploid stages of male germ cells. Moreover, immunochemical analysis of mouse cauda epididymal sperm using an affinity-purified antibody against bovine pancreatic trypsinogen shows that TESP4 is localized only in the sperm acrosome and is released during the acrosome reaction induced by calcium ionophore A23187. These findings may open a new point of view regarding the molecular mechanisms of the sperm/egg interactions, including the sperm penetration of the egg zona pellucida.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.