Fig. 4: Forward genetic screening identified a bZIP transcription factor NOSR-1 required for NoSB formation.

A Schematic diagram of the forward genetic screening to search for factors required for NoSB formation in C. elegans nuclei. B DIC and fluorescence microscopy images of nuclei in the indicated L4 stage animals expressing the mCherry::DIS-3 (scale bar, 5 μm). The yellow dashed line represents the nucleus, and the yellow arrows indicate NoSB (see also in Fig. 4E). C Schematic of the nosr-1 exon structure. nosr-1 (ust303) is the mutant obtained from the forward genetic screen. The deletion alleles ust307, ust308, and ust309 were constructed by CRISPR/Cas9 technology (see Methods). D Quantification of NoSB in hypodermic cells in the indicated animals. Red dots indicate the percentage of hypodermis cells containing NoSB in each L4 stage worm. n indicates the number of independent animals tested. A two-tailed t-test was performed to determine statistical significance. 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 (see also in Fig. 4F). E Top: Schematic diagram of the formation of nucleolar rings, enlarged nucleolar vacuoles and nucleolar stress bodies (NoSBs) in rpl-14(RNAi) animals. Bottom: Images of mCherry::DIS-3 transgene in nosr-1(-);rpl-14(RNAi) animals (scale bar, 5 μm). The green arrows indicate the nucleolar ring. F Quantification of nucleolar rings and NoSB in hypodermic cells in the indicated animals. Every dot indicates the percentage of hypodermis cells containing NoSB or nucleolar rings in each worm. Red dots indicate NoSB and green dots indicate nucleolar rings. n indicates the number of independent animals tested. A two-tailed t-test was performed to determine statistical significance. All images were taken by the Leica THUNDER imaging System. Source data are provided as a Source Data file.