Fig. 1.

AO127 mutant animals are deficient in rnaset2. (A) AO127 mutants displayed a higher uptake of AO compared with WT embryos, quantifiable by flow cytometry. (Note the intense fluorescence common to both animals is a result of AO within the lumen of the pharynx and intestine, autofluorescence of residual yolk, and ready uptake of AO by olfactory neurons and hair cells within neuromasts.) (Scale bars: 200 μm.) (B) Sequencing of the gene zgc:113369, coding for the zebrafish orthologue of human RNASET2, identified a T-to-A transversion in the mutant sample. (C) RT-PCR indicates a dramatic down-regulation of rnaset2 mRNA in AO127 mutants compared with WT siblings. β-Actin serves as a control for RNA integrity and equal input cDNA. (D) Suppression of excess AO staining in AO127 mutants by injection of WT rnaset2 mRNA but not mutant mRNA.