Fig. 1

The formation of the adult dermal skeleton and pharyngeal teeth is affected in fls mutant zebrafish.

A) Alizarin red-stained wild type adult zebrafish shows staining of the scales, fin rays, dermal bones of the skull as well as the pharyngeal teeth along ceratobranchial 5 (bracket, B) and (C) gill rakers along both the anterior (antGr) and posterior edge (postGr) of non-teeth bearing ceratobranchials. D) fls^te370f shows loss of dermal skeletal structures of the fin rays, scales and alteration in the shape of the skull. Additionally, fls^te370f shows loss of pharyngeal teeth (E) and gill rakers (F). G–I) The Topless allele (fls^dt3Tpl) shows a dominant effect on scalation and tooth/gill raker formation while not affecting lepidotrichial growth. J–L) Expressivity of fls^dt3Tpl is sensitive to a modifier in the Tü strain leading to a “weak” fls^dt3Tpl phenotype; fls^dt3Tpl homozygotes were phenotypically identical to fls^te370f (not shown). The fang allele of fls, fls^tfang, isolated in a non-complementation screen with fls^te370f, shows no effect on fin development while exhibiting partial loss of scales (M), teeth (N), and gill rakers (O). Transallelic tfang/te370f zebrafish exhibit an intermediate phenotype between homozygous fls(te370f) and fls(tfang) (P–R).