Construct: Amino acid replacement: D38A. Amino acid replacement: E367A.
Embryos exhibit the class IV phenotype. Expression of two copies causes transformation of T1 to a T2 identity with complete loss of the T1 beard, head segments are also transformed to a T2 identity (all normal head structures are missing and two or three T2-like denticle belts are seen on the head). Embryos also exhibit an absence of Keilin's organs, shortened denticle belts and a failure of germ band retraction.
Phosphorylation at sites 1 and 4 by Ck2, or by a kinase with very similar substrate specificity, is important for modulating Antp activity in vivo.