The rough boundaries of the P excision mutation were mapped to a restriction fragment. The deletion takes out 5' noncoding and some coding sequence of chic. The position of the restriction fragment on the reference sequence was inferred by a FlyBase curator
actin filament & eye disc | somatic clone
photoreceptor cell & eye disc | somatic clone
A chic221 heterozygous mutant background modifies the actin remodelling and subsequent basolateral invasion of epithelial cells seen in flies expressing CskGD9345 in a stripe of cells at the anterior/posterior boundary of the larval wing disc under the control of Scer\GAL4ptc-559.1.
A chic221 heterozygous background enhances the patterning defects found in Scer\GAL4GMR.PF>cindrdsRNA.PC.PD.Scer\UAS mutants. The mean interommatidial precursor cell number and the number of cone and/or 1[o] cell errors is increased in these double mutants.
The Btk29Ak00206 salivary gland phenotype is enhanced in chic221, Btk29Ak00206 double mutants as more cells remain on the surface at stage 14 compared with Btk29Ak00206 single mutants. The amount of actin disorganization that precedes the salivary gland phenotype is also increased in these double mutants. Additionally, chic221, Btk29Ak00206 double mutants exhibit a higher level of uncoordinated endoreplication at early stage 12, prior to the invagination defects, than Btk29Ak00206 single mutants.
cibP/+ ; chic221/+ double heterozygotes show a cib-like mutant phenotype, with a partially split fan-shaped body (it is split along the midline in 10% of flies), a ventrally opened ellipsoid body and a normal mushroom body. This interaction is synergistic. Addition of chic221 to cibP/Y flies exacerbates the cibP phenotype; cibP/Y ; chic221/+ males have a fan-shaped body that is split in the middle, a strongly disturbed ellipsoid body (it is flat and very often split along the midline) and disorganised mushroom body medial lobes that rarely reach their normal position. cibP/Y ; chic221/+ males are also sterile and show a thoracic bristle defect with shorter and forked ends than normal.
One copy of chic221 suppresses the frequency of midline crossovers seen in Khc::Ggal\MLCKKA.ftz embryos. However, Khc::Ggal\MLCKKA.ftz chic221 double mutant embryos show major defects in the formation of the central nervous system axon scaffold, with gaps or thinning of the longitudinal connectives, as axon bundles appear to preferentially cross the midline.