scholarly journals Chromatoid body and small RNAs in male germ cells

Reproduction ◽  
2011 ◽  
Vol 142 (2) ◽  
pp. 195-209 ◽  
Author(s):  
Oliver Meikar ◽  
Matteo Da Ros ◽  
Hanna Korhonen ◽  
Noora Kotaja

The chromatoid body (CB) is a germ granule in the cytoplasm of postmeiotic haploid round spermatids that is loaded with RNA and RNA-binding proteins. Following the discovery of small non-coding RNA-mediated gene regulation and the identification of PIWI-interacting RNAs (piRNAs) that have crucial roles in germ line development, the function of the CB has slowly begun to be revealed. Male germ cells utilise small RNAs to control the complex and specialised process of sperm production. Several microRNAs have been identified during spermatogenesis. In addition, a high number of piRNAs are present both in embryonic and postnatal male germ cells, with their expression being impressively induced in late meiotic cells and haploid round spermatids. At postmeiotic stage of germ cell differentiation, the CB accumulates piRNAs and proteins of piRNA machinery, as well as several other proteins involved in distinct RNA regulation pathways. All existing evidence suggests a role for the CB in mRNA regulation and small RNA-mediated gene control, but the mechanisms remain uncharacterised. In this review, we summarise the current knowledge of the CB and its association with small RNA pathways.

PLoS ONE ◽  
2012 ◽  
Vol 7 (6) ◽  
pp. e39729 ◽  
Author(s):  
Valeria Messina ◽  
Oliver Meikar ◽  
Maria Paola Paronetto ◽  
Sara Calabretta ◽  
Raffaele Geremia ◽  
...  

Development ◽  
2020 ◽  
pp. dev.191916
Author(s):  
Danelle Wright ◽  
Makoto Kiso ◽  
Yumiko Saga

NANOS2 and NANOS3 are evolutionarily conserved RNA-binding proteins involved in murine germ cell development. NANOS3 is required for protection from apoptosis during migration and gonadal colonization in both sexes, whereas NANOS2 is male-specific and required for the male-type differentiation of germ cells. Ectopic NANOS2 rescues the functions of NANOS3, but NANOS3 cannot rescue NANOS2 function even though its expression is up-regulated in Nanos2-null conditions. It is unknown why NANOS3 cannot rescue NANOS2 function and it is unclear whether NANOS3 plays any role in male germ cell differentiation. To address these questions, we made conditional Nanos3/Nanos2 knockout mice and chimeric mice expressing chimeric NANOS proteins. Conditional double knockout of Nanos2 and 3 led to the rapid loss of germ cells, and in vivo and in vitro experiments revealed that DND1 and NANOS2 binding is dependent on the specific NANOS2 zinc finger structure. Moreover, murine NANOS3 failed to bind CNOT1, an interactor of NANOS2 at its N-terminal. Collectively, our study suggests that the inability of NANOS3 to rescue NANOS2 function is due to poor DND1 recruitment and CNOT1 binding.


Reproduction ◽  
2011 ◽  
Vol 142 (6) ◽  
pp. 803-817 ◽  
Author(s):  
Mai Nguyen-Chi ◽  
Dominique Morello

Changes in mRNA translation and degradation represent post-transcriptional processes operating during gametogenesis and early embryogenesis to ensure regulated protein synthesis. Numerous mRNA-binding proteins (RBPs) have been described in multiple animal models that contribute to the control of mRNA translation and decay during oogenesis and spermatogenesis. An emerging view from studies performed in germ cells and somatic cells is that RBPs associate with their target mRNAs in RNA–protein (or ribonucleoprotein) complexes (mRNPs) that assemble in various cytoplasmic RNA granules that communicate with the translation machinery and control mRNA storage, triage, and degradation. In comparison withXenopus, Caenorhabditis elegans, orDrosophila, the composition and role of cytoplasmic RNA-containing granules in mammalian germ cells are still poorly understood. However, regained interest for these structures has emerged with the recent discovery of their role in small RNA synthesis and transposon silencing through DNA methylation. In this review, we will briefly summarize our current knowledge on cytoplasmic RNA granules in murine germ cells and describe the role of some of the RBPs they contain in regulating mRNA metabolism and small RNA processing during gametogenesis.


2019 ◽  
Author(s):  
Maciej Jerzy Smialek ◽  
Erkut Ilaslan ◽  
Marcin Piotr Sajek ◽  
Aleksandra Swiercz ◽  
Damian Mikolaj Janecki ◽  
...  

ABSTRACTMammalian Pumilio (PUM) proteins are sequence-specific, RNA-binding proteins with wide-ranging roles, including germ cell development that has functional implications in fertility. Although human PUM1 and PUM2 are closely related to each other and recognize the same RNA binding motif, there is some evidence for functional diversity, particularly related to their roles in fertility. Here, by RNA sequencing (RNA-Seq) approaches, we identified separate mRNA pools regulated by PUM1 and PUM2 proteins in human male germ cells. Using global mass spectrometry-based profiling, we identified distinct PUM1- and PUM2-bound putative protein cofactors, most of them involved in RNA processing. Combinatorial analysis of RNA-Seq and mass spectrometry findings revealed that PUM1 and PUM2 may form distinct RNA-regulatory networks, with different roles in human reproduction and testicular tumorigenesis. Our findings highlight the functional divergence and versatility of PUM paralogue-based post-transcriptional regulation, offering insight into the mechanisms underlying their diverse biological roles and diseases resulting from their dysfunction.


2011 ◽  
Vol 22 (16) ◽  
pp. 2875-2885 ◽  
Author(s):  
Mai Nguyen Chi ◽  
Jacques Auriol ◽  
Bernard Jégou ◽  
Dimitris L. Kontoyiannis ◽  
James M.A. Turner ◽  
...  

Posttranscriptional mechanisms are crucial to regulate spermatogenesis. Accurate protein synthesis during germ cell development relies on RNA binding proteins that control the storage, stability, and translation of mRNAs in a tightly and temporally regulated manner. Here, we focused on the RNA binding protein Embryonic Lethal Abnormal Vision (ELAV) L1/Human antigen R (HuR) known to be a key regulator of posttranscriptional regulation in somatic cells but the function of which during gametogenesis has never been investigated. In this study, we have used conditional loss- and gain-of-function approaches to address this issue in mice. We show that targeted deletion of HuR specifically in germ cells leads to male but not female sterility. Mutant males are azoospermic because of the extensive death of spermatocytes at meiotic divisions and failure of spermatid elongation. The latter defect is also observed upon HuR overexpression. To elucidate further the molecular mechanisms underlying spermatogenesis defects in HuR-deleted and -overexpressing testes, we undertook a target gene approach and discovered that heat shock protein (HSP)A2/HSP70-2, a crucial regulator of spermatogenesis, was down-regulated in both situations. HuR specifically binds hspa2 mRNA and controls its expression at the translational level in germ cells. Our study provides the first genetic evidence of HuR involvement during spermatogenesis and reveals Hspa2 as a target for HuR.


2021 ◽  
Vol 11 ◽  
Author(s):  
Mikel Irastortza-Olaziregi ◽  
Orna Amster-Choder

Coupled transcription-translation (CTT) is a hallmark of prokaryotic gene expression. CTT occurs when ribosomes associate with and initiate translation of mRNAs whose transcription has not yet concluded, therefore forming “RNAP.mRNA.ribosome” complexes. CTT is a well-documented phenomenon that is involved in important gene regulation processes, such as attenuation and operon polarity. Despite the progress in our understanding of the cellular signals that coordinate CTT, certain aspects of its molecular architecture remain controversial. Additionally, new information on the spatial segregation between the transcriptional and the translational machineries in certain species, and on the capability of certain mRNAs to localize translation-independently, questions the unanimous occurrence of CTT. Furthermore, studies where transcription and translation were artificially uncoupled showed that transcription elongation can proceed in a translation-independent manner. Here, we review studies supporting the occurrence of CTT and findings questioning its extent, as well as discuss mechanisms that may explain both coupling and uncoupling, e.g., chromosome relocation and the involvement of cis- or trans-acting elements, such as small RNAs and RNA-binding proteins. These mechanisms impact RNA localization, stability, and translation. Understanding the two options by which genes can be expressed and their consequences should shed light on a new layer of control of bacterial transcripts fate.


PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e42695 ◽  
Author(s):  
Rita L. Peruquetti ◽  
Sara de Mateo ◽  
Paolo Sassone-Corsi

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