Fig. 1

Impaired T cell development in fish homozygous for a missense mutation in zbtb17.

(A) Representative microphotographs of wild-type (top panel) and homozygous mutant (bottom panel) zebrafish embryos hybridized with probes specific for rag1 (purple circle) and gh (green circle) at 5 dpf. (B) Eye diameter (means ± s.e.m.) for the three different zbtb17 genotypes (numbers of fish indicated) without (black bars) and with injection of mouse Zbtb17 wild-type mRNA (mRNA) determined at 4 dpf. (C) Thymopoietic indices (means ± s.e.m.) for the three different zbtb17 genotypes without (black bars) and with injection of mouse Zbtb17 wild-type mRNA (mRNA) determined at 4 dpf. (D) Representative sequence traces covering part of exon 10 sequences of wild-type fish (left panel), heterozygotes (middle panel) and homozygous mutants (right panel). The C > A transversion occurs at nucleotide position 1684 of ENSDARG00000074548 (http://www.ensembl.org/Danio_rerio/Transcript/Summary?db=core;g=ENSDARG00000074548;r=23:24525127-24540083;t=ENSDART00000114840). (E) Representative microphotographs of zbtb17 mutant embryos after injection of mouse Zbtb17 mRNA hybridized with probes specific for rag1 and gh at 96 hpf. The thymic rudiments (marked by expression of rag1) are encircled in purple, the hypophysis (marked by expression of gh) is encircled in green. (F) Schematic of the ZBTB17 proteins, indicating the position of known domains, including the 12 zinc finger modules. Below, an alignment of partial protein sequences of vertebrate ZBTB17 proteins around the critical region of the ninth zinc finger (marked in schematic) is shown. The presumptive zinc-coordinating (brackets), DNA-contacting (solid circles) and hydrophobic (asterisks) amino acid residues are marked. Source sequences: human, H. sapiens, Genbank accession number NP_001274532.1; mouse, M. musculus, Genbank accession number NP_033567.2; platypus, Ornithorhynchus anatinus, Genbank accession number XP_003429656.1; chicken, G. gallus, Genbank accession number NP_001263229.1; xenopus, X. tropicalis, Genbank accession number NP_001011141.2; zebrafish, D. rerio, Genbank accession number XP_003201251.1; shark, C. milii, Genbank accession number XP_007905152.1. (G) Structure of the ninth zinc finger of the mouse Zbtb17 protein (source code 2LVT); the mutated Q43 residue is indicated in purple. Scale bar, 100 μm.