Fig. 4: mRNA positioning correlates with translation on germ granules.
From: Direct observation of translational activation by a ribonucleoprotein granule
a, Example image of translating (arrows) and non-translating (arrowheads) mRNA. Blue, Vasa; magenta, suntag mRNA; green, scFv–GFP. b, Relative frequency histogram with KDE curve of translating and non-translating mRNA distribution in germplasm. A total of 12,684 translating and 19,712 non-translating foci from 7 images over 7 embryos were plotted. c, The translating fraction in each bin of the x axis from seven embryos was calculated and plotted. The data are the mean ± s.d. The average translating fraction in the entire germplasm is indicated as the dashed line. The translating fractions on the granule surface (0 ≤ x ≤ 200 nm) were compared with the ones within granules (x < 0) or ones not localized to granules (x > 400 nm) using two-tailed Welch’s t-test. d, A model of the predicted orientation and distribution of translating and non-translating mRNAs in germ granules. e, Distribution of total suntag-nanos mRNA stained by suntag probes in stage 1 embryos and stage 14 oocytes. A total of 6,468 foci from images of 4 oocytes and 32473 foci from images of 7 embryos were mapped. f, Detecting the 5′ and 3′ sequence of native nanos mRNA in wild-type oocytes. The orthogonal views of the outlined region are shown on the right. Scale bar, 0.3 µm. g, PCC analysis between nanos 3′ and 5′ signals in oocytes and embryos. n = 4 embryos and 4 oocytes. h, PCC analysis of Oskar signal with nanos 5′ or 3′ signal in oocytes. Statistics in g and h: two-tailed Welch’s t-test. n = 4 oocytes for both conditions. In g and h, the data are the mean ± s.d. i, Distribution of RPS6 (anti-RPS6, magenta) in germplasm. The germ granules are marked by VasaGFP (green)46. j, z-stacks of 40 images of germplasm with germ granules at the centre or without germ granules were made and z-projected by summing slices. Scale bar, 0.25 µm. k, suntag mRNA (magenta) distribution on germ granules (Vasa) in embryos treated with DMSO (control) and harringtonine. l, Relative frequency histogram with KDE of total suntag smFISH foci distribution in embryos treated with DMSO (2,618 foci from 5 embryos) or harringtonine (8,545 foci from 4 embryos).
