Sm and Sm-like proteins are RNA-binding factors found in all three domains of life. Eukaryotic Sm proteins play essential roles in pre-mRNA splicing, forming the cores of spliceosomal small nuclear ribonucleoproteins (snRNPs). Recently, Sm proteins have been implicated in the specification of germ cells. However, a mechanistic understanding of their involvement in germline specification is lacking and a germline-specific RNA target has not been identified. We demonstrate that Drosophila SmB and SmD3 are specific components of the oskar messenger ribonucleoprotein (mRNP), proper localization of which is required for establishing germline fate and embryonic patterning. Importantly, oskar mRNA is delocalized in females harboring a hypomorphic mutation in SmD3, and embryos from mutant mothers are defective in germline specification. We conclude that Sm proteins function to establish the germline in Drosophila, at least in part by mediating oskar mRNA localization.
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http://dx.doi.org/10.1242/dev.042721 | DOI Listing |
EMBO Rep
January 2025
Department of Biological Sciences, Hunter College, City University of New York, New York, NY, 10065, USA.
Processing bodies (P-bodies) are cytoplasmic membrane-less organelles which host multiple mRNA processing events. While the fundamental principles of P-body organization are beginning to be elucidated in vitro, a nuanced understanding of how their assembly is regulated in vivo remains elusive. Here, we investigate the potential link between ER exit sites and P-bodies in Drosophila melanogaster egg chambers.
View Article and Find Full Text PDFNat Cell Biol
November 2024
Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
Ribonucleoprotein (RNP) granules are membraneless condensates that organize the intracellular space by compartmentalization of specific RNAs and proteins. Studies have shown that RNA tunes the phase behaviour of RNA-binding proteins, but the role of intermolecular RNA-RNA interactions in RNP granules in vivo remains less explored. Here we determine the role of a sequence-specific RNA-RNA kissing-loop interaction in assembly of mesoscale oskar RNP granules in the female Drosophila germline.
View Article and Find Full Text PDFBiochem Soc Trans
October 2024
Department of Biological Sciences, Hunter College, City University of New York, New York, NY 10065, USA.
Advances in the study of mRNAs have yielded major new insights into post-transcriptional control of gene expression. Focus on the spatial regulation of mRNAs in highly polarized cells has demonstrated that mRNAs translocate through cells as mRNA:protein granules (mRNPs). These complex self-assemblies containing nuclear and cytoplasmic proteins are fundamental to the coordinated translation throughout cellular development.
View Article and Find Full Text PDFbioRxiv
July 2024
Department of Biological Sciences, Hunter College, City University of New York, NY, 10065 USA.
Processing bodies (P-bodies) are cytoplasmic membrane-less organelles which host multiple mRNA processing events. While the fundamental principles of P-body organization are beginning to be elucidated , a nuanced understanding of how their assembly is regulated remains elusive. Here, we investigate the potential link between ER exit sites and P-bodies in egg chambers.
View Article and Find Full Text PDFNat Cell Biol
August 2024
Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
Biomolecular condensates organize biochemical processes at the subcellular level and can provide spatiotemporal regulation within a cell. Among these, ribonucleoprotein (RNP) granules are storage hubs for translationally repressed mRNA. Whether RNP granules can also activate translation and how this could be achieved remains unclear.
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