Haploid spermatids exhibit translationally repressed mRNAs.

During spermiogenesis, DNA-binding histones are replaced by protamines. DNA-protamine-interactions result in chromatin condensation causing cessation of transcription in elongating spermatids. Thus, in haploid spermatids, processes of transcription and translation need to be temporally uncoupled in order to ensure protein synthesis in transcriptionally silent germ cells. Post-transcriptional events, such as processing, transport, and storage of mRNAs, therefore, play important roles in determining when transcripts become functionally available for translation. This review focuses on mechanisms of translational regulation in haploid spermatids and male infertility caused by defects of translational control processes.