88.21 is a novel aldh1a2 allele.
A, B. Islet1 (isl1) expression was used in a haploid ENU screen to identify mutants in endocrine pancreas development. Dorsal view of 30 hpf wild type embryo with isl1 expression in the CNS and endocrine pancreas (A; black arrow indicates expression in pancreas) and 88.21 mutant embryo with isl1 expression in the CNS, but not in the endoderm (B). C–E. Lateral view of live wild type (C), 88.21 (D), and neckless aldh1a2i26 (E) embryos at day 5. F. Linkage analysis using CA repeat markers on pooled genomic DNA from 88.21 mutants and pooled genomic wild type DNA. Marker z10441 amplifies a 450 bp band and a faint 500 bp band in the mutant pool compared to a faint 450 bp band and a 500 bp band in the wild type pool. Marker z8693 amplifies two bands at 250 bp and 300 bp in the mutant pool compared to 250 bp, 300 bp as well as a 400 bp band in the wild type pool. White arrow points to lack of 400 bp band in mutant. G. Schematic drawing of part of linkage group 7 (LG7), showing the location of z10441 and z8693 and aldh1a2 (in red) in reference to these markers. H–J. Sequence analysis of pooled 88.21 mutant (MT) genomic DNA and pooled wild type (WT) genomic DNA (H, J), as well as of individual mutant (MT) and wild type (WT) embryos (I). 88.21 fish carry a mutation that converts Gly484 to Arg (in red, and outlined in brackets in J) located in the catalytic domain. K. Schematic of Aldh1a2 protein and the location of the aldh1a2 mutant alleles aldh1a2i26, aldh1a2u11 and 88.21/aldh1a2um22.