An FRT-flanked Crk 3151bp genomic rescue construct (corresponding to the exact sequence deleted in CrkΔattP) inserted in the TI{TI}CrkΔattP locus. (The FRT sites are inserted 104 bp upstream of the transcription start site and 99 bp downstream of the end of the 3' UTR, and allow deletion via the FLP recombinase to facilitate production of females whose germlines are homozygous mutant.)
Maternal-zygotic and maternal-only Crk-mutant embryos (i.e. all progeny from CrkΔattP heterozygous males crossed to CrkΔattP homozygous females rescued to adulthood by CrkFRT.gen, but in which the Crk rescue segment has been FLP-excised) frequently exhibit morphological defects, which can be denticle belt deletion or fusion, ventral or dorsal holes, severe pattern disruption and/or cuticle fragments.
Maternal Crk-mutant embryos from CrkΔattP homozygous females rescued to adulthood by CrkFRT.gen, but in which the Crk genomic segment has been FLP-excised, frequently exhibit defects in cellularization, leading to variable size yolk channels
