ISOLATION, CHARACTERIZATION AND COMPLETE NUCLEOTIDE-SEQUENCE OF A GALLERIA-MELLONELLA CDNA CODING FOR THE FOLLICLE CELL-SPECIFIC YOLK PROTEIN, YP4

An ovariole-specific yolk polypeptide cDNA from Galleria mellonella wa s isolated from a cDNA library constructed using vitellogenic ovariole poly (A)+ RNA, by differential screening with the ovariole and day-0 male pupal poly (A)+ RNA. The Ov11 cDNA hybridized to a 1.1 kb message from the ovariole but not from male pharate adults, ovariectomized ph arate adults or day-5 last instar larvae. Developmental Northern analy sis showed that this message is expressed only during vitellogenic sta ges, In situ hybridization of digoxigenin-dUTP labeled Ov11 cDNA to th e day-8 pharate adult ovariole showed that only follicle cells express the Ov11 gene. The 960 bp Ov11 cDNA is nearly full-length, containing a single open reading frame coding for a 286 amino acid polypeptide w ith a hydrophobic signal sequence and two potential N-glycosylation an d tyrosine sulfation sites, The fact that Ov11 cDNA codes for the 37 k Da ovariole-specific yolk protein, YP4, was confirmed by the N-termina l amino acid sequence analysis of purified YP4, Genomic Southern analy sis suggests that the yp4 gene is a single copy gene and PCR analysis using the 5' and 3' end primers of the cDNA indicates that the yp4 gen e is intronless within the coding region. Copyright (C) 1996 Elsevier Science Ltd.