Imprecise excision of the progenitor insertion, resulting in a deletion that removes both tnc transcription start sites.
Homozygous have a normal hindgut lumen at stage 13, show a slight reduction in hindgut lumen at stage 14 and show a clear reduction in its diameter at stage 16. tnc13c/Df(3R)BSC655 embryos also show the narrow hindgut lumen phenotype.
The cells of the hindgut have reduced apical circumferences compared to wild type a stage 16 in mutant embryos. This is particularly evident in the small intestine. In the posterior large intestine, cells are less stretched along the lumen circumference than normal. In the anterior large intestine there are more cells along the lumen length and fewer cells surrounding the lumen circumference than normal, indicating a higher degree of cell intercalation than normal. The outer tube diameter of the hindgut is consistently reduced compared to wild type.
Tracheal dorsal trunks are slightly shorter than normal at stage 16 in homozygous embryos.
