Dfd16 mutant clones encompassing the maxillary palp region have deleted palps and disordered suborbital vibrissae. Clones on the posterior of the head display altered postorbital and occipital bristles.
Mutant embryos show a fusion of the maxillary and mandibular segments.
Stage 12 Dfd16/Dfd12 embryos show displacement of the maxillary segment and mandibular segments due to an accumulation of supernumerary cells at the ventral side of both segments. Cells in the ventral part of the maxillary segment are elongated, instead of round like wild-type cells.
The mouthhooks are missing and the lateralgraten are shortened in mutant larvae.
In Dfd12/Dfd16 embryos, the maxillary cirri primordium and the anterior boundary of the dorsal ridge, between the mandibular and maxillary segments, are missing. The number of apoptotic cells in the maxillary segment is reduced when compared to wild-type.
Homozygous embryos lack cirri, mouth hooks, the ventral organ and the dental sclerite, the lateral process is truncated and the lateral bar of the H-piece is missing. A portion of the maxillary sense organ is missing and the remaining structure does not align properly with the antennal sense organ.
Mutants lack mouth hooks and cirri.
Dfd12/Df(3R)Scr embryos lack the mouthhooks and cirri, while the more posterior mouthparts are unaffected. The mouthhook and cirri defects are rescued in Dfd12/Df(3R)Scr embryos expressing DfdScer\UAS.cBa under the control of Scer\GAL469B. Head involution fails in these animals and the posterior mouthparts fail to form. Dfd12/Dfd16 embryos lack the mouthhooks and cirri, while the more posterior mouthparts are unaffected.
The morphology of the gnathal lobes is abnormal in Dfd16 embryos.
Homozygous embryos lack mouth hooks and cirri and the lateralgraten are shortened.
Dfd16 Scr4 double homozygous embryos exhibit failure of the labial lobes to migrate ventrally or internalise. Ectopic external sensory organs, derived from failure of the labial lobes to internalise, are the same as for Scr- embryos.
Double mutant combinations with cnc- embryos show additive effects in the head skeleton.
Dfd is required but not sufficient for 1.28 expression.
No salivary gland defects.
In Ubxhs.PG embryos that are homozygous for Dfd16 the cirri and mouthhooks are missing.
Failure head involution and head defects: defects in structures derived from the maxillary, mandibular and premandibular regions of the embryonic head. Mitotic recombination analysis suggests that in the adult Dfd affects the head structures homologous to those of the embryo.