254bp deletion within exon 2, producing a truncated peptide that contains the first 86 amino acids of scu, followed by 7 out of frame residues and a premature stop codon.
eye photoreceptor cell & mitochondrion | somatic clone
spermatocyte & mitochondrion
spermatocyte & nucleolus
scu3127 is completely viable during embryogenesis, and shows lethality at the third larval instar stage. The number of homozygous clones produced in the adult cuticle is reduced compared to the wild-type controls in twin mosaic analysis. Homozygous clones in the adult cuticle have normal morphology. Homozygous clones in the eye do not contain recognisable ommatidia and photoreceptors within the clone do not differentiate normally; the rhabdomere is not formed correctly, the cell usually contains large multilayered accumulations of membranous material and the mitochondria are smaller and fewer than wild-type, with swollen crestae. Testis size is reduced in males examined before the onset of lethality. Spermatocytes are organised into smaller groups of cells than normal in pupal testes, and contain large numbers of fat-containing vesicles. The nucleoli are not as compact as in wild-type cells and the number of mitochondria are reduced.
Somatic clonal analysis indicates that scu+ activity is required for cell survival and that this requirement is cell autonomous. The degree of reduction of testis size varies in the following order: scu174 > scu4058 > scuS152 > scu3127.