MicroRNA dilution during oocyte growth disables the microRNA pathway in mammalian oocytes

0537847 - ÚMG 2021 RIV GB eng J - Journal Article
Kataruka, Shubhangini - Modrák, Martin - Kinterová, Veronika - Malík, Radek - Zeitler, D.M. - Horvat, Filip - Kaňka, Jiří - Meister, G. - Svoboda, Petr
MicroRNA dilution during oocyte growth disables the microRNA pathway in mammalian oocytes.
Nucleic Acids Research. Roč. 48, č. 14 (2020), s. 8050-8062. ISSN 0305-1048. E-ISSN 1362-4962
R&D Projects: GA MŠMT LO1419; GA MŠMT(CZ) LM2015047; GA MŠMT(CZ) LM2018131
Institutional support: RVO:68378050 ; RVO:61388971 ; RVO:67985904
Keywords : 3 abundance classes * gene-expression * messenger-rna * endogenous sirnas * let-7 represses * mouse oocytes * binding * dicer * cell * transcriptome
OECD category: Reproductive biology (medical aspects to be 3); Developmental biology (UZFG-Y); Biochemistry and molecular biology (MBU-M)
Impact factor: 16.971, year: 2020
Method of publishing: Open access
https://academic.oup.com/nar/article/48/14/8050/5866099

MicroRNAs (miRNAs) are ubiquitous small RNAs guiding post-transcriptional gene repression in countless biological processes. However, the miRNA pathway in mouse oocytes appears inactive and dispensable for development. We propose that marginalization of the miRNA pathway activity stems from the constraints and adaptations of RNA metabolism elicited by the diluting effects of oocyte growth. We report that miRNAs do not accumulate like mRNAs during the oocyte growth because miRNA turnover has not adapted to it. The most abundant miRNAs total tens of thousands of molecules in growing (empty set 40 mu m) and fully grown (empty set 80 mu m) oocytes, a number similar to that observed in much smaller fibroblasts. The lack of miRNA accumulation results in a 100-fold lower miRNA concentration in fully grown oocytes than in somatic cells. This brings a knockdown-like effect, where diluted miRNAs engage targets but are not abundant enough for significant repression. Low-miRNA concentrations were observed in rat, hamster, porcine and bovine oocytes, arguing that miRNA inactivity is not mouse-specific but a common mammalian oocyte feature. Injection of 250,000 miRNA molecules was sufficient to restore reporter repression in mouse and porcine oocytes, suggesting that miRNA inactivity comes from low-miRNA abundance and not from some suppressor of the pathway.
Permanent Link: http://hdl.handle.net/11104/0315680