Specific isoforms of Squid, a Drosophila hnRNP, perform distinct roles in Gurken localization during oogenesis
| Autor: | Richard L. Kelley, Amanda Norvell, Trudi Schüpbach, Kristina Wehr |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Cytoplasm
Genotype Recombinant Fusion Proteins Receptors Cytoplasmic and Nuclear RNA-binding protein Karyopherins Biology Models Biological Animals Genetically Modified Oogenesis Untranslated Regions Translational regulation Genetics medicine Animals Drosophila Proteins Humans Protein Isoforms RNA Messenger Transgenes Nuclear protein Nuclear export signal Ovum Cell Nucleus Models Genetic Sequence Homology Amino Acid Ovary Alternative splicing Gene Expression Regulation Developmental Nuclear Proteins RNA-Binding Proteins Transforming Growth Factor alpha Immunohistochemistry Molecular biology Cell biology Cell nucleus medicine.anatomical_structure Transforming Growth Factors Insect Proteins Drosophila Female Nuclear transport Drosophila Protein Research Paper Developmental Biology |
| Zdroj: | Genes & Development. 13:864-876 |
| ISSN: | 0890-9369 |
| DOI: | 10.1101/gad.13.7.864 |
| Popis: | Heterogeneous nuclear RNA-binding proteins, hnRNPs, have been implicated in nuclear export of mRNAs in organisms from yeast to humans. A germ-line mutation in a Drosophila hnRNP, Squid (Sqd)/hrp40, causes female sterility as a result of mislocalization of gurken (grk) mRNA during oogenesis. Alternative splicing produces three isoforms, SqdA, SqdB, and SqdS. Here we show that these isoforms are not equivalent; SqdA and SqdS perform overlapping but nonidentical functions in grk mRNA localization and protein accumulation, whereas SqdB cannot perform these functions. Furthermore, although all three Sqd isoforms are expressed in the germline cells of the ovary, they display distinct intracellular distributions. Both SqdB and SqdS are detected in germ-line nuclei, whereas SqdA is predominantly cytoplasmic. We show that this differential nuclear accumulation is correlated with a differential association with the nuclear import protein Transportin. Finally, we provide evidence that grk mRNA localization and translation are coupled by an interaction between Sqd and the translational repressor protein Bruno. These results demonstrate the isoform-specific contributions of individual hnRNP proteins in the regulation of a specific mRNA. Moreover, these data suggest a novel role for hnRNPs in localization and translational regulation of mRNAs. |
| Databáze: | OpenAIRE |
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