Fig. 1: Imaging translation of nanos mRNA in Drosophila embryos.
From: Direct observation of translational activation by a ribonucleoprotein granule
a, Left: schematic of a Drosophila embryo. Germplasm (blue) is located at the posterior pole of the embryo. The dashed square represents the region imaged by confocal microscopy and presented in b. Right: schematic of a translating suntag-nanos mRNA. A repetitive array of SunTag epitopes is added to the N-terminus of the nanos CDS. Nascent SunTag peptides are detected by scFv–GFP binding and suntag mRNA is detected by smFISH probes (magenta dashed line). b, A representative confocal image of the posterior pole of an embryo expressing Vasa–mApple (blue), suntag-nanos (mRNA stained by suntag smFISH probes, magenta), and scFv–GFP (green). Outlined regions in germplasm and soma are magnified and presented in c. c, Magnified images of germplasm and soma show the different translation activities in these two parts of the embryo. d, Left: quantification of the percentage of translating mRNA in the soma (n = 4) and the germplasm (n = 7). Right: zoomed confocal images showing examples of a translating mRNA that co-localizes with scFv–GFP signal (arrowhead) and two non-translating mRNA that do not co-localize with scFv–GFP signal (arrows). e, Quantification of suntag-nanos mRNA translation in the soma and the posterior pole of embryos with mCherry knockdown (KD) or osk KD. n = 5 for all experiments. f, Osk-bcd 3′ UTR expression induces germplasm and translation of suntag-nanos mRNA at the anterior pole. Top: Oskar protein is immunostained with anti-Oskar antibody. Bottom: translation of suntag-nanos mRNA in native germplasm at the posterior and ectopic germplasm at the anterior, which are quantified in g. n = 7 (anterior), 6 (soma) and 7 (posterior). In d,e,g, the data are the mean ± s.d.; n, number of the embryos used for measurement.
