Fig. 2: Mutation of exosome ribonucleases induced NoSB formation.
A Schematic diagram of forward genetic screening to search for factors suppressing NoSB formation in C. elegans nuclei. B Schematic of the gene structure of exosome genes. exos-4.2 (ust243) and exos-10 (ust242) are the mutants obtained from the forward genetic screen; exos-1 (ust57) and exos-10 (ok2269) are obtained from the National Bioresource Project and the CGC; dis-3 (ust56), a conserved amino acid Arg363, was mutated to cysteine38,40. C DIC and fluorescence microscopy images of nuclei in hypodermal cells of respective L4 stage animals expressing the mCherry::DIS-3 (scale bar, 5 μm). The yellow dashed line represents the nucleus outlines, and the yellow arrows indicate NoSB (see also in Fig. 2F). D Quantification of NoSB in hypodermic cells in exosome mutants. Red dots indicate the percentage of hypodermis cells containing NoSB in each worm. n indicates the number of independent animals tested. For box plots, the horizontal line represents the median value, the lower and upper quartiles represent the 25th and 75th percentile, and the whiskers show the maximum and minimum values; a two-tailed t-test was performed to determine statistical significance (see also in Fig. 2E). E The size of NoSB in exosome mutants. Blue dots indicate the area of NoSB. n of nucleoli from 20 independent animals were measured. F DIC and fluorescence microscopy images of C. elegans nuclei in hypodermal cells after actinomycin D treatment for 48 h. The nucleoplasm is marked by mCherry::DIS-3 (magenta), and the nucleolus is marked by FIB-1::GFP (green). Three times were repeated independently with similar results. All images were taken by the Leica THUNDER imaging System. Source data are provided as a Source Data file.
