In lab4 mutant clones in the anterior head, vibrissae are disrupted or missing, the ventral edge of the eye is deleted, and maxillary palps are missing. In posterior head clones, novel bristles appear in the postgena.
The average number of crystal cells per embryo is reduced in homozygous stage 13-14 embryos compared to wild type.
No salivary gland defects.
No change in the spatial distribution of ae mRNA.
Hemizygous animals die at the embryonic/first larval instar border. A variable cuticle phenotype is seen, with the severity of the defects correlating with the degree of failure of head involution. The frontal sac appears collapsed, and the pharynx occupies a more anterior position than normal. The salivary glands are missing. Homozygous mutant clones in the head have a mutant phenotype - novel tissue is seen in the postgena and other structures are disrupted.