Nucleotide substitution: G?A.
Predicted to result in a truncated protein lacking all of the 13 tetratricopeptide repeats of the fand protein.
Amino acid replacement: W69term.
G13593989A
G?A
W69term | fand-PA
W69term
Nonsense mutation (TGG to TAG) at Trp codon.
The salivary gland placodes of fas1 embryos appear identical to wild type at the gross morphological level, but the cells in the placode are stacked upon each other in two or three rows and are variably elongated (in contrast to wild type where the placode consists of a monolayer of uniformly elongated cells). At the stage when the dorsal-posterior pit forms in the salivary gland placode in wild-type embryos, a slight indentation is seen near the centre of the placode in fas1 embryos, suggestive of cell shape changes. The invaginating pit is not as deep or wide as in wild-type embryos. Cells at the centre of the pit appear elongated with basally positioned nuclei, however, the surrounding cells in the pit are round and found in multiple layers. Cells in the anterior and posterior parts of the gland also form multi-layered placodes. Although the initial indentation occurs at slightly variable locations in different embryos of similar age, the pit observed in late-stage mutant embryos is trough-shaped and uniformly located close to the centre of the placode. The salivary glands are eventually internalised, despite gross abnormalities in cell shape. The internalised gland is comprised of a mixture of elongated and wedge-shaped cells. Cells in the anterior and posterior parts of the gland are multi-layered. After internalisation, the salivary glands fuse into one dome-shaped organ which is close to the ventral surface. The gland is multi-layered and has the remnants of a potentially contiguous lumen. When internalisation is complete, the surface morphology of the salivary pit is similar to wild type.
Malpighian tubules arrest early in their morphogenesis in homozygous embryos. The tubules are spherical. The tubules have a short lumen that is approximately normal in width. The tip cells are present. The hindgut is extremely short.
Embryos have poorly developed cuticle with necrotic patches and an abnormal head. First visible in extended-germ-band stage.
fandfas-1/fandH124 has tracheal primordium | embryonic stage phenotype, non-suppressible by bnlUAS.cSa/Scer\GAL469B
The lack of primary tracheal branching characteristic for fandfas-1/fandH124 transheterozygous embryos cannot be rescued by expression of bnlScer\UAS.cSa under the control of Scer\GAL469B (which on its own causes excessive tracheal branching).
fandfas-1/fandH124 is rescued by Scer\GAL4da.PU/fandUASp.Tag:MYC
fandfas-1/fandH124 is rescued by fandUASp.Tag:MYC/Scer\GAL4Abd-B-LDN
fandfas-1/fandH124 is partially rescued by Scer\GAL4da.PU/fandUASp.Tag:MYC/Scer\GAL80btl
fandfas-1/fandH124 is not rescued by Scer\GAL4btl.PS/fandUASp.Tag:MYC
The fandfas-1 allele fails to complement both fandP218 and fandH124 alleles.
The tracheal branching and central nervous defects characteristic for fandfas-1/fandH124 embryos are fully rescued by combination with a single copy of fand+tGa. The lack of tracheal branching is also rescued by expression of fandScer\UAS.T:Hsap\MYC when driven by Scer\GAL4da.PU or Scer\GAL4Abd-B-LDN and partially so when driven by Scer\GAL4da.PU combined with Scer\GAL80btl (to block the expression in tracheal cells), while it cannot be rescued by Scer\GAL4btl.PS-driven expression.