Sexual reproduction depends on the production of male and female gametes to perpetuate the specie. In male, spermatozoa are produced continuously by the testis throughout adulthood. Spermatogenesis is divided into three successive phases: the mitotic proliferation of spermatogonia, the meiotic divisions generating haploid spermatids and spermiogenesis, which is accompanied with morphological changes of spermatids into spermatozoa. Sertoli cells, one of the somatic cells of the testis, are essential regulators of spermatogenesis as their function is to sustain germ cell development through structural, nutritional and hormonal support. In addition, spermatogenesis is tightly controlled by stage- and cellular-specific gene expression programs regulated by both transcriptional and post-transcriptional mechanisms. The goal of my thesis was to improve our understanding of the molecular mechanisms regulating gene expression during normal or defective spermatogenesis in mouse. We wished to widen our knowledge of idiopathic infertility associated with testicular dysfunction.