Fig. 2

Nucleolar and ribosome biogenesis factors are dysregulated in rbpms2 DMs.

a Schematic of nucleolar development from mitosis to prophase I arrest. Briefly, upon entry into meiosis, the singular nucleolus of the germ cell disassembles. As the cell progresses through prophase I, new nucleoli are amplified through seeding by rDNA loci and nucleoli begin to expand. Nucleolar expansion, maturation, and ribosome biogenesis continues up until meiotic arrest at diplotene. b, c Transmission electron micrographs of 35 dpf wildtype and rbpms2 DM oocytes. Dashed lines outline oocyte cytoplasmic membrane and black arrowheads indicate nucleoli. Scale bar is 5 µM. d Quantification of number of nucleoli per oocyte in wildtype (n = 2 fish) and rbpms2 DM (n = 2 fish) gonads. A minimum of 20 prophase I cells per genotype were analyzed and categorized into the following groups: 1 nucleolus (blue), 2–4 nucleoli (purple), and 4+ nucleoli (green). Source data are provided as a Source Data file. e, f p-Ubtf (active RNA pol I; purple) and RNA pol II (yellow) immunostaining in 31-35 dpf wildtype (rbpms2a^ae30; rbpms2b^sa9329 heterozygous mutant; n = 4) and rbpms2 DM (rbpms2a^ae30; rbpms2b^sa9329 double homozygous mutant; n = 4) germ cells. Enlarged views of boxed regions show representative localization of p-Ubtf in wildtype and rbpms2 DM oocytes and white arrows indicate p-Ubtf localization in nucleoli. Scale bar for all images is 20 µM. g, h Fibrillarin (yellow) immunostaining in 29-33 dpf wildtype (rbpms2a^ae30; rbpms2b^sa9329 heterozygous mutant; n = 4) and rbpms2 DM (rbpms2a^ae30; rbpms2b^sa9329 double homozygous mutant; n = 4) germ cells. Enlarged views of boxed regions show representative localization of Fibrillarin in wildtype and rbpms2 DM oocytes. Scale bar for all images is 20 µM. e–h Germ cells are labeled by Ddx4 (teal) and nuclei are labeled with DAPI (white).