It has been suggested that many novel RNA-binding proteins (RBPs) are required for gametogenesis, but the necessity of few of these proteins has been functionally verified. Here, we identified one RBP, Rbm46, and investigated its expression pattern and role in zebrafish reproduction. We found that rbm46 is maternally provided and specifically expressed in the germ cells of gonadal tissues using in situ hybridization, reverse transcription-PCR, and quantitative real-time polymerase chain reaction (qRT-PCR). Two independent rbm46 mutant zebrafish lines were generated via the transcription activator-like effector nuclease technique. Specific disruption of rbm46 resulted in masculinization and infertility in the mutants. Although the spermatogonia appeared grossly normal in the mutants, spermatogenesis was impaired, and meiosis events were not observed. The introduction of a tp53M214K mutation could not rescue the female-to-male sex-reversal phenotype, indicating that rbm46 acts independently of the p53-dependent apoptotic pathway. RNA sequencing and qRT-PCR subsequently indicated that Rbm46 might be involved in the posttranscriptional regulation of functional genes essential for germ cell development, such as nanos3, dazl, and sycp3, during gametogenesis. Together, our results reveal for the first time the crucial role of rbm46 in regulating germ cell development in vivo through promotion of germ cell progression through meiosis prophase I.
Summary sentence
We generated zebrafish with rbm46 mutations using transcription activator-like effector nucleases to demonstrate that the disruption of rbm46 results in masculinization and infertility through impairment of germ cell progression through meiosis prophase I.
Graphical Abstract
Schematic diagram showing the proposed function of Rbm46, which is critical for germ cell progression through meiosis prophase I in zebrafish. All the mutants are infertile males with spermatogonia or premeiotic cells. Meiosis defects were observed and Rbm46 is potentially involved in the posttranscriptional regulation of functional genes during spermatogenesis, such as nanos3, dazl, sycp3, in mutants.
