Ile at residue 92 replaced by Asn.
Nucleotide substitution: C?T. Nucleotide substitution: T?A. Amino acid replacement: I92N. Mutations are in the second exon.
ile92->asn92
T10054268A
T?A
I92N | Yp1-PA; I92N | Yp1-PB
I92N
Osmium zinc iodide staining in Golgi of ovarian follicles is wild type, but no yolk spheres label.
Yolk protein aggregates found in space between plasmalemma and vitelline membranes and embedded within the vitelline membrane itself. This interferes with correct assembly of the egg shell membranes, causing sterility.
Heterozygous females are fertile and secrete Yp1 protein at 18oC, but are sterile and do not secrete Yp1 protein at 29oC. Homozygous females are sterile and fail to secrete Yp1 protein at both temperatures. Unusual electron-dense material is found in the subbasement membrane space of many fat body cells in heterozygotes at 29oC. This subbasement membrane material (SBMM) is often located near the plasma membrane, and consists of two types of material, a material which sometimes appears fibrous with a crystalline, lattice-shaped morphology, and an amorphous material. The SBMM contains yolk. Homozygous females reared at either 20 or 29oC have smaller fat body cells than normal, and SBMM is present. Yp1ts1/Df(1)C52 females have an abnormal fat body. SBMM is present in females reared at 29oC.
Homozygous follicle cells differ from wild-type by having larger secretory vesicles, forming clumps of an electron-dense secretory component within the developing vitelline membrane (this component disperses after secretion in the wild-type), accumulating more tubules in the cortical ooplasm of vitellogenic oocytes, and possessing altered yolk spheres. Homozygous ovaries transplanted into wild-type hosts show no improvement in the secretory granule phenotype and slight improvement of the vitelline membrane clump phenotype, but show amelioration of the oocyte tubule and yolk sphere phenotypes.
Homozygous females are sterile.
Heterozygous females lay normal eggs at 18oC whereas all eggs produced at 29oC are collapsed.
female-sterile Homozygous female sterile at 18oC and homo- and heterozygous female sterile at 29oC, producing flaccid eggs and reduced amounts of yolk protein at the high temperature. (Bownes and Hodson, 1980). Yp1ts1 is female sterile over Df(1)C52, a deficiency for the Yp1 locus (Postlethwait and Shirk, 1981).
Germ line clonal analysis shows that Yp1 function is required in the soma.
Yp1 gene product deficiency in haemolymph and eggs due to reduced rate of secretion.