An Hsp70 promoter drives expression of cDNA sequence encoding the Antp coding region (no 5'UTR sequence is present), with phosphomimetic mutations introduced into all 4 putative CKII phosphorylation sites (amino acid replacements T35E, S84E, T358E and S364E).
Embryos exhibit a slight block in head development and a partial reduction in the cephalopharyngeal skeleton. This is the class I phenotype. Development of the thorax and abdomen are unaffected.