Faculty Opinions recommendation of The cytoplasmic-localized, cytoskeletal-associated RNA binding protein OsTudor-SN: evidence for an essential role in storage protein RNA transport and localization.

Previous studies in transgenic mice have established the importance of the 3' untranslated region (UTR) of the spermatid-specific protamine-1 (Prm-1) mRNA in its translational control during male germ cell development. To clone genes that mediate the translational repression or activation of the Prm-1 mRNA, we screened cDNA expression libraries made with RNA from pachytene spermatocytes and round spermatids, with an RNA probe corresponding to the 3' UTR of Prm-1. We obtained six independent clones that encode Spnr, a spermatid perinuclear RNA-binding protein. Spnr is a 71-kD protein that contains two previously described RNA binding domains. The Spnr mRNA is expressed at high levels in the testis, ovary, and brain, and is present in multiple forms in those tissues. Immunolocalization of the Spnr protein within the testis shows that it is expressed exclusively in postmeiotic germ cells and that it is localized to the manchette, a spermatid-specific microtubular array. Although the Spnr protein is expressed too late to be directly involved in the translational repression of Prm-1 specifically, we suggest that the Spnr protein may be involved in other aspects of spermatid RNA metabolism, such as RNA transport or translational activation.

Download Full-text

RNA-binding protein DUS16 plays an essential role in primary miRNA processing in the unicellular alga Chlamydomonas reinhardtii

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1523230113 ◽

2016 ◽

Vol 113 (38) ◽

pp. 10720-10725 ◽

Cited By ~ 10

Author(s):

Tomohito Yamasaki ◽

Masayuki Onishi ◽

Eun-Jeong Kim ◽

Heriberto Cerutti ◽

Takeshi Ohama

Keyword(s):

Chlamydomonas Reinhardtii ◽

Essential Role ◽

Binding Proteins ◽

Rna Binding ◽

Rna Binding Proteins ◽

Binding Protein ◽

Rna Binding Protein ◽

Mature Mirnas ◽

Mirna Biogenesis ◽

Dsrna Binding

Canonical microRNAs (miRNAs) are embedded in duplexed stem–loops in long precursor transcripts and are excised by sequential cleavage by DICER nuclease(s). In this miRNA biogenesis pathway, dsRNA-binding proteins play important roles in animals and plants by assisting DICER. However, these RNA-binding proteins are poorly characterized in unicellular organisms. Here we report that a unique RNA-binding protein, Dull slicer-16 (DUS16), plays an essential role in processing of primary-miRNA (pri-miRNA) transcripts in the unicellular green alga Chlamydomonas reinhardtii. In animals and plants, dsRNA-binding proteins involved in miRNA biogenesis harbor two or three dsRNA-binding domains (dsRBDs), whereas DUS16 contains one dsRBD and also an ssRNA-binding domain (RRM). The null mutant of DUS16 showed a drastic reduction in most miRNA species. Production of these miRNAs was complemented by expression of full-length DUS16, but the expression of RRM- or dsRBD-truncated DUS16 did not restore miRNA production. Furthermore, DUS16 is predominantly localized to the nucleus and associated with nascent (unspliced form) pri-miRNAs and the DICER-LIKE 3 protein. These results suggest that DUS16 recognizes pri-miRNA transcripts cotranscriptionally and promotes their processing into mature miRNAs as a component of a microprocessor complex. We propose that DUS16 is an essential factor for miRNA production in Chlamydomonas and, because DUS16 is functionally similar to the dsRNA-binding proteins involved in miRNA biogenesis in animals and land plants, our report provides insight into this mechanism in unicellular eukaryotes.

Download Full-text

The RNA-binding protein Igf2bp3 is critical for embryonic and germline development in zebrafish

10.1101/2020.06.23.167163 ◽

2020 ◽

Author(s):

Yin Ho Vong ◽

Lavanya Sivashanmugam ◽

Andreas Zaucker ◽

Alex Jones ◽

Karuna Sampath

Keyword(s):

Germ Cells ◽

Essential Role ◽

Molecular Mechanisms ◽

Rna Binding ◽

Binding Protein ◽

Primordial Germ Cells ◽

Rna Binding Protein ◽

Germline Development ◽

Early Embryos ◽

Cytoplasmic Complex

AbstractThe ability to reproduce is essential in all branches of life. In metazoans, this process is initiated by formation of the germline, a group of cells that are destined to form the future gonads, the tissue that will produce the gametes. The molecular mechanisms underlying germline formation differs between species. In zebrafish, development of the germline is dependent on the specification, migration and proliferation of progenitors called the primordial germ cells (PGCs). PGC specification is dependent on a maternally provided cytoplasmic complex of ribonucleoproteins (RNPs), the germplasm. Here, we show that the conserved RNA-binding protein (RBP), Igf2bp3, has an essential role during early embryonic development and germline development. Loss of Igf2bp3 leads to an expanded yolk syncytial layer (YSL) in early embryos, reduced germline RNA expression, and mis-regulated germline development. Maternal mutants affecting igf2bp3 exhibit abnormal PGCs and adult igf2bp3 mutants show male biased sex ratios. Therefore, Igf2bp3 is required for normal embryonic and germline development.

Download Full-text