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Fig. 4
Epistasis analysis of the il7 mutation. (A) Thymopoietic capacities measured in fish of the 9 genotypes arising from an intercross of il7+/−;il7r+/− double-heterozygous parents. Each data point represents 1 fish; data are mean ± SEM. Representative whole-mount RNA in situ hybridization results for the key genotypes are shown at the bottom. (B) Comparison of phenotypes of the 2 single mutants (il7−/− and il7r−/−) and the il7−/−;il7r−/− double mutant; the latter phenotype is compared with the expected phenotype (multiplicative model). The thymopoietic capacity observed in the double mutant is significantly higher than that expected from the combination of the single mutants, calculated under the assumption of no genetic interaction, indicative of alleviating genetic interaction. (C) Thymopoietic capacities measured in fish of the 9 genotypes arising from an intercross of il7+/−;/jak3+/− double-heterozygous parents. Each data point represents 1 fish; data are mean ± SEM. Representative whole-mount RNA in situ hybridization results for the key genotypes are shown at the bottom. (D) Comparison of phenotypes of the 2 single mutants (il7−/− and jak3−/−) and the il7−/−;jak3−/− double mutant with the expected phenotype. The observed thymopoietic capacity observed in the double mutant is significantly higher than that expected from the combination of the single mutants, indicative of alleviating genetic interaction. (E) Thymopoietic capacities measured in crlf2 morphants of 3 different il7 genotypes. Representative whole-mount RNA in situ hybridization results are shown at the right. (F) The degree of reduction of thymopoietic activity in the presence of the crlf2 antisense oligonucleotide is independent of il7 genotype, indicating that the 2 effects are genetically independent (no genetic interaction). (G) RT-PCR analysis of crlf2 cDNA structures resulting from interference with splicing of the pre-mRNA transcripts by an antisense oligonucleotide targeting the splice donor site of exon 3 (SD3).