Abstract
SummaryIn Drosophila oocytes, gurken/TGF-α mRNA is essential for establishing the future embryonic axes. gurken remains translationally silent during transport from its point of synthesis in nurse cells to its final destination in the oocyte, where it associates with the edge of processing bodies. Here we show that, in nurse cells, gurken is kept translationally silent by the lack of sufficient Orb/CPEB, its translational activator. Processing bodies in nurse cells have a similar protein complement and ultrastructure to those in the oocyte, but they markedly less Orb and do not associate with gurken mRNA. Ectopic expression of Orb in nurse cells at levels similar to the wild-type oocyte dorso-anterior corner at mid-oogenesis is sufficient to cause gurken mRNA to associate with processing bodies and translate prematurely. We propose that controlling the spatial distribution of translational activators is a fundamental mechanism for regulating localized translation.
Highlights
The regulation of translation in space and time is essential for a variety of physiological and developmental processes, such as axis specification in Drosophila and Xenopus, cell migration in fibroblasts, and synaptic plasticity in mammalian neurons (Medioni et al, 2012)
We found that small foci of grk mRNA, similar but weaker in intensity than oocyte transport particles (Figure S2A and S2A0), are evenly distributed in the nurse cell cytoplasm, with only a minority associated with the edge of nurse cell P bodies (Figures 2A and 2A00)
We found that the key P body markers maternal expression at 31B (Me31B) (Figure 3A) and Bru (Figure 3B) have a similar enrichment in nurse cells and the oocyte and that ribosomes are excluded from the nurse cell P bodies as they are from P bodies in the oocyte (Figure 3C)
Summary
Localized transcripts that determine polarity are thought to be silenced during their transport by binding to translational repressors. Davidson et al show that gurken mRNA, which sets up the primary Drosophila body axes, is instead regulated through lack of a translational activator, Orb, during its transport. Highlights d gurken mRNA is not silenced by known repressors during its transport d In nurse cells, gurken mRNA is not associated with processing bodies d In nurse cells, lack of sufficient Orb/CPEB silences gurken mRNA translation d In oocytes, gurken mRNA is associated with Orb on processing bodies and translated.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
