Fig. 7: Nuclear localization of the Microprocessor is required for development.

a Diagram of the N-terminal PASH-1[Δ12-148]::GFP deletion protein with the WW domain (WW), double-stranded RNA-binding domains (dsRBDs), and GFP indicated. b AlphaFold3-predicted structures of the Microprocessor from humans (with only DROSHA and DGCR8) and C. elegans. The N-termini of human DGCR8 (residues 1-275) and C. elegans PASH-1 (residues 12-148) are highlighted. c Representative images of wild-type, mCherry::drsh-1 pash-1::GFP, and mCherry::drsh-1 pash-1[Δ12-148]::GFP animals. 1–2 gravid adults, larvae, and eggs are visible. The scale bars are 0.3 mm. At least four representative adults for each strain were imaged. d Numbers of progeny produced by pash-1::GFP (unaltered), pash-1[Δ12-148]::GFP (Δ12-148), and pash-1::GFP::NES (NES) animals grown at 20 °C. Error bars are SD. n = 10 (unaltered), 19 (Δ12-148), or 14 (NES) animals. p-values were calculated using two-tailed Mann-Whitney U tests. e PASH-1::GFP, PASH-1[Δ12-148]::GFP, and mCherry::DRSH-1 expression in embryos. A wild-type embryo is shown as a control. The scale bars are 0.03 mm. At least 6 representative embryos for each strain were imaged. f AlphaFold3-predicted structure of the C. elegans Microprocessor containing PASH-1[Δ12-148]. PASH-1’s dimerization region (residues 148-266) and the PASH-1-DRSH-1 interacting region (PASH-1 helix [residues 497-513], DRSH-1 RIIIDa [residues 683-803], and DRSH-1 RIIIDb [residues 830-981]) are highlighted. g Diagram of the PASH-1::GFP protein fused to a nuclear export signal (NES, pink) with the WW domain (WW), dsRBDs, and GFP indicated. h PASH-1::GFP, PASH-1::GFP::NES, and mCherry::DRSH-1 expression in embryos. A wild-type embryo lacking GFP is shown as a control. The scale bars are 0.03 mm. At least six representative embryos for each strain were imaged. i Representative images of pash-1::GFP (control) and pash-1::GFP::NES animals. F1 animals are first-generation segregates from a heterozygous parent. F2 are descended from a homozygous parent. White arrows point to arrested embryos, and black arrows point to arrested larvae. The scale bars are 0.3 mm. At least 2 representative individuals for each strain were imaged. j Arrested pash-1::GFP::NES larvae and embryos. The scale bars are 0.03 mm. Three representative individuals were imaged. Source data are provided as a Source Data file.