Xenbase Image ID: 140012
Fig. 4. Xenopus pax6 mutants have abnormal eyes without lenses. (A–D) Offspring from crosses between F0 mosaic mutation carriers (A) or F1 carriers (B–D) showed a consistent phenotype in the eye (red arrows) regardless of the genotype of mutant alleles. F0 crosses (st.716 female #2 x male #3) created a variety of combinations of genotypes in mutant offspring (A), whereas 25% of offspring from F1 crosses (i.e., parents are not mosaic) have a single homozygous (B) or compound heterozygous (C,D) mutant genotype as expected. Note that mutants homozygous for a 13-bp deletion in exon 7 (B) are indistinguishable from other compound heterozygous mutants, regardless of the combination of exon 7 mutations (A, top right embryo), combination of exon 7 and exon 9 mutations (A, bottom right embryo and D), or combination of exon 9 mutations (C). Each embryo shown here was genotyped except for phenotypic wild-type embryos in C and D, thus shown as +/?. Judging from the mutation profiles (see Table S1), we could infer the origins of mutated alleles of offspring from F0 crosses, or in the case of F1 crosses, the genotypes of parents are known in advance, thus we show offspring genotypes in order of parental female locus/male locus except for the top wild-type embryo in (B), where the parental origin of alleles is undeterminable. Actual sequences of mutations can be found in Table S1. (E) Cross sections of embryos marked by red (mutant) and green (wild-type) asterisks in (A) to show morphology of the eyes. The wild-type embryo (green asterisk) has a lens (white arrowhead) and the retina is surrounded by retinal pigment epithelial (RPE) and separated from the brain (green arrowhead), whereas the mutant embryo (red asterisk) has no lens and the retina is disorganized (black arrowhead) and still connected to the brain (red arrowhead). (F) Schematic presentation of proteins encoded by the mutations shown here. Also refer to Fig. 1 for color codes. Exon 7 mutations cause truncation at the C-terminus of the paired domain (located between amino acid residues 4–131), whereas exon 9 mutations cause truncation in the middle of the homeodomain (located between amino acid residues 212–272). Truncations in many cases but not all are followed by unrelated amino acids due to the frameshift. Note that mutant embryos shown in (C) make almost identical mutant proteins with only one amino acid change at position 238, thus this is very close to being a homozygous mutation. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Image published in: Nakayama T et al. (2015)
Copyright © 2015. Image reproduced on Xenbase with permission of the Publisher, Elsevier B. V.
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