Non-coding RNA in Spermatogenesis and Epididymal Maturation
Testicular germ and somatic cells express many classes of small ncRNAs, including Dicer-independent PIWI-interacting RNAs, Dicer-dependent miRNAs, and endogenous small interfering RNA. Several studies have identified ncRNAs that are highly, exclusively, or preferentially expressed in the testis and epididymis in specific germ and somatic cell types. Temporal and spatial expression of proteins is a key requirement of successful spermatogenesis and large-scale gene transcription occurs in two key stages, just prior to transcriptional quiescence in meiosis and then during spermiogenesis just prior to nuclear silencing in elongating spermatids. More than 60 % of these transcripts are then stockpiled for subsequent translation. In this capacity ncRNAs may act to interpret and transduce cellular signals to either maintain the undifferentiated stem cell population and/or drive cell differentiation during spermatogenesis and epididymal maturation. The assignation of specific roles to the majority of ncRNA species implicated as having a role in spermatogenesis and epididymal function will underpin fundamental understanding of normal and disease states in humans such as infertility and the development of germ cell tumours.
KeywordsNoncoding RNA Primordial germ cell Gonocyte Differentiation Meiosis Spermatogenesis Spermiogenesis Epididymis Sertoli cell
Funding The authors gratefully acknowledge the financial assistance to EAM, JEH and BN by the Australian Research Council, National Health and Medical Research Council and the University of Newcastle. JEH is the recipient of an Australian Research Council DECRA Award. This work was supported by the ARC Centre of Excellence in Biotechnology and Development (CE0348239) to EAM and NHMRC (APP 1062371) to BN, EAM and JEH.
Conflict of Interest The authors declare that there is no conflict of interest as defined by the guidelines of the International Committee of Medical Journal Editors (ICMJE; www.icmje.org).
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