Maintenance of Miranda Localization in Drosophila Neuroblasts Involves Interaction with the Cognate mRNA

• Published in: Current biology 2017-07, Vol.27 (14), p.2101-2111.e5
• Main Authors: Ramat, Anne, Hannaford, Matthew, Januschke, Jens
• Format: Article
• Language: English
• Subjects: Animals; asymmetric cell division; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Drosophila; Drosophila melanogaster - genetics; Drosophila melanogaster - growth & development; Drosophila melanogaster - physiology; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Female; Larva - genetics; Larva - physiology; Life Sciences; Male; Mitosis; mRNA localization; nanobody; Neural Stem Cells - metabolism; neuroblasts; polarity; RNA, Messenger - genetics; RNA, Messenger - metabolism
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2017.06.016

How cells position their proteins is a key problem in cell biology. Targeting mRNAs to distinct regions of the cytoplasm contributes to protein localization by providing local control over translation. Here, we reveal that an interdependence of a protein and cognate mRNA maintains asymmetric protein distribution in mitotic Drosophila neural stem cells. We tagged endogenous mRNA or protein products of the gene miranda that is required for fate determination with GFP. We find that the mRNA localizes like the protein it encodes in a basal crescent in mitosis. We then used GFP-specific nanobodies fused to localization domains to alter the subcellular distribution of the GFP-tagged mRNA or protein. Altering the localization of the mRNA resulted in mislocalization of the protein and vice versa. Protein localization defects caused by mislocalization of the cognate mRNA were rescued by introducing untagged mRNA coding for mutant non-localizable protein. Therefore, by combining the MS2 system and subcellular nanobody expression, we uncovered that maintenance of Mira asymmetric localization requires interaction with the cognate mRNA. [Display omitted] •Nanobody technology and the MS2 system can be used to alter mRNA localization•miranda mRNA localizes in two distinct pools in Drosophila neuroblasts in mitosis•Asymmetric Miranda localization requires an mRNA-dependent maintenance step Ramat et al. combine the MS2 system and nanobody expression to alter the subcellular localization of mRNA. Shifting basally localized miranda mRNA in Drosophila neuroblasts to the apical pole resulted in Miranda protein localization defects. Miranda protein and cognate mRNA interaction positively feeds back on asymmetric Miranda localization.