Functional genomic analysis identifies miRNA repertoire regulating C. elegans oocyte development

Abstract

Oocyte-specific miRNA function remains unclear in mice and worms because loss of Dgcr8 and Dicer from mouse and worm oocytes, respectively, does not yield oogenic defects. These data lead to several models: (a) miRNAs are not generated in oocytes; (b) miRNAs are generated but do not perform an oogenic function; (c) functional oocyte miRNAs are generated in a manner independent of these enzymes. Here, we test these models using a combination of genomic, expression and functional analyses on the C. elegans germline. We identify a repertoire of at least twenty-three miRNAs that accumulate in four spatial domains in oocytes. Genetic tests demonstrate that oocyte-expressed miRNAs regulate key oogenic processes within their respective expression domains. Unexpectedly, we find that over half of the oocyte-expressed miRNAs are generated through an unknown Drosha independent mechanism. Thus, a functional miRNA repertoire generated via Drosha dependent and independent pathways regulates C. elegans oocyte development.

Circular RNA profiling in the oocyte and cumulus cells reveals thatcircARMC4is essential for porcine oocyte maturation

“…This potential interplay between circRNA and miRNA could provide a reference for elucidating regulatory mechanisms of these DECs in oocyte meiotic maturation. Indeed, recent studies have shown that maternal miRNA participates in regulating oocyte maturation and early embryo development in several species, including pigs (Wright et al, 2016), medaka (Gay et al, 2018), and C.elegans (Minogue et al, 2018). Specifically, miRNA-7 was found to inhibit epidermal growth factor receptor (EGFR) expression in human cancer cells (Webster et al, 2009) and EGFR signaling is required for cumulus cell expansion and oocyte maturation (Prochazka et al, 2017), suggesting that miRNA-7 may negatively regulate oocyte maturation.…”

“…This may be due to the imperfectness of in vitro culture conditions currently used that cannot achieve the optimal maturational outcomes, and there is inadequate information regarding the unique molecular mechanisms of porcine oocyte meiotic maturation (Sun and Nagai, 2003; Prather et al, 2009). It is known that oocyte maturation is intricately regulated by cumulus cell or oocyte itself derived non-coding RNAs, such as microRNA (miRNA) (Dallaire and Simard, 2016; Wright et al, 2016; Li et al, 2017b; Gay et al, 2018; Minogue et al, 2018), endogenous small interference RNA (siRNA) (Suh et al, 2010) and long non-coding RNA (lncRNA) (Taylor et al, 2015). Recently, circular RNA (circRNA) has received increasing attention in multiple biological research fields.…”

In Situ Hybridization for Detecting Mature MicroRNAs In Vivo at Single‐Cell Resolution

“…Moreover, miRNA expression seems restricted to unique cell types within a given tissue. For example, in C. elegans , 29 oocyte‐expressed miRNAs are localized in four different spatial patterns that are restricted to the developing and maturing oocytes in the germline (Minogue, Tackett, Atabakhsh, Tejada, & Arur, ). The analysis allowed spatial resolution of each miRNA relative to another in a tissue comprising multiple cell types.…”

<p>The Importance of Small Non-Coding RNAs in Human Reproduction: A Review Article</p>

“…1,13,14 Synthesis and degradation of miRNAs have been proven to play an important role during oogenesis and embryonic development. 15,16 Global miRNA expression profiling has shown that miRNAs are inherited maternally and almost 60% of them are being lost during the maternal-zygotic transition from one to two cell stages. 17,18 It seems that dynamic degradation and synthesis of miRNAs coexist during the development of the preimplantation mouse embryo with an overall elevation in miRNAs toward the blastocyst stage.…”