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DAZL relieves miRNA-mediated repression of germline mRNAs by controlling poly(A) tail length in zebrafish
Yasuaki Takeda1, Yuichiro Mishima, Toshinobu Fujiwara
1Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan.
Background:
During zebrafish embryogenesis, microRNA (miRNA) miR-430 contributes to restrict Nanos1 and TDRD7 to primordial germ cells (PGCs) by inducing mRNA deadenylation, mRNA degradation, and translational repression of nanos1 and tdrd7 mRNAs in somatic cells. The nanos1 and tdrd7 3'UTRs include cis-acting elements that allow activity in PGCs even in the presence of miRNA-mediated repression.
Methodology/Principal Findings:
Using a GFP reporter mRNA that was fused with tdrd7 3'UTR, we show that a germline-specific RNA-binding protein DAZ-like (DAZL) can relieve the miR-430-mediated repression of tdrd7 mRNA by inducing poly(A) tail elongation (polyadenylation) in zebrafish. We also show that DAZL enhances protein synthesis via the 3'UTR of dazl mRNA, another germline mRNA targeted by miR-430.
Conclusions/Significance:
Our present study indicated that DAZL acts as an "anti-miRNA factor" during vertebrate germ cell development. Our data also suggested that miRNA-mediated regulation can be modulated on specific target mRNAs through the poly(A) tail control.
Insights
Germline RNA-binding protein DAZL counteracts microRNA repression in zebrafish primordial germ cells by controlling mRNA polyadenylation, ensuring proper germ cell development. This reveals a novel anti-miRNA mechanism in vertebrates.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- MicroRNA (miRNA) miR-430 regulates germ cell development in zebrafish by targeting Nanos1 and TDRD7.
- miRNA-mediated repression involves mRNA deadenylation, degradation, and translational repression in somatic cells.
- Germ cell-specific cis-acting elements in target mRNA 3'UTRs permit function despite miRNA activity.
Purpose of the Study:
- To investigate the role of germline-specific RNA-binding protein DAZ-like (DAZL) in modulating miRNA regulation.
- To determine how DAZL affects the repression of target mRNAs, specifically TDRD7 and DAZL itself.
Main Methods:
- Utilized a GFP reporter mRNA fused with the tdrd7 3'UTR to assess miRNA repression.
- Analyzed the effect of DAZL on polyadenylation of reporter mRNA.
- Investigated DAZL's influence on protein synthesis from its own mRNA via the 3'UTR.
Main Results:
- DAZL relieves miR-430-mediated repression of tdrd7 mRNA by inducing poly(A) tail elongation.
- DAZL enhances protein synthesis of dazl mRNA through its 3'UTR.
- Demonstrated DAZL's function as an anti-miRNA factor in zebrafish germ cells.
Conclusions:
- DAZL acts as an "anti-miRNA factor" in vertebrate germ cell development.
- miRNA regulation of specific target mRNAs can be modulated via poly(A) tail control.
- This study uncovers a novel mechanism for regulating gene expression in germ cells.
