Fig. 7: nos mRNA translation depends on germ granule biphasic architecture.
From: Spatial organization of translation and translational repression in two phases of germ granules
a STED images of wild-type and tudA36/Df(2 R)PurP133 (tudA36) embryos immunostained with anti-Osk antibody. Fluorescence intensity was recorded along the white dotted line (right). b Measurement of germ granule size in wild-type and tudA36/Df(2 R)PurP133 (tudA36) embryos from images as in (a). Horizontal bars represent the mean and SD. ****p < 0.0001 using unpaired two-tailed Student’s t-test. p = 2.4 × 10−248. c Immuno-smFISH of nos-suntag-nos/+; nos-scFv-GFP/+ (wild-type) and nos-suntag-nos tudA36/Df(2 R)PurP133; nos-scFv-GFP/+ (tudA36) embryos with anti-GFP nanobody (green) to reveal scFv-GFP and suntag smFISH probe (magenta). d Percentage of suntag-nos mRNA clusters colocalizing with scFv-GFP foci, i.e., undergoing translation, in nos-suntag-nos/+; nos-scFv-GFP/+ (wild-type) and nos-suntag-nos tudA36/Df(2 R)PurP133; nos-scFv-GFP/+ (tudA36) embryos from images as in (c). ****p < 0.0001 using χ2 test. p = 2 × 10−77. e STED images of immunostaining of nos-suntag-nos/+; nos-scFv-GFP/+ (wild-type) and nos-suntag-nos tudA36/Df(2 R)PurP133; nos-scFv-GFP/+ (tudA36) embryos with anti-Osk antibody (magenta) and anti-GFP nanobody (green) to reveal scFv-GFP. f STED images of immunostaining of wild-type and tudA36/Df(2 R)PurP133 (tudA36) embryos with anti-Osk (green) and anti-Aub (magenta) antibodies. g Quantification of colocalization between Osk and Aub using PCC(Costes). Black circles represent the mean and error bars represent SEM. The number of embryos is indicated (n). ns: non-significant using unpaired two-tailed Student’s t-test. p = 0.42. h STED images of immunostaining of wild-type and tudA36/Df(2 R)PurP133 (tudA36) stage 14 oocytes with anti-Osk antibody. i Measurement of germ granule size in wild-type and tudA36/Df(2 R)PurP133 (tudA36) stage 14 oocytes from images as in (h). Horizontal bars represent the mean and SD. ****p < 0.0001 using unpaired two-tailed Student’s t-test. p = 6.2 × 10−209. j Model of functional compartmentalization of germ granules. The scheme represents a biphasic germ granule with main protein components accumulating in the outer phase (green). Repressed mRNAs in a condensed state accumulate towards the granule core. Translation takes place in the outer phase and at the periphery of the granule. Translational activators (eIF3 and PABP) are found in the outer phase. Translated mRNAs are less condensed and anchored to the granule core from their 3′region, whereas their 5′end is oriented toward the outer phase and periphery of the granule. mRNAs translocate from the core to the outer phase during translation. Scale bars: 1 µm. Source data are provided as a Source Data file.
