Vitellogenin in Drosophila melanogaster: sequence of the yolk protein I gene and its flanking regions

Abstract

We have isolated recombinant DNA clones coding for female specific proteins from Drosophila melanogaster. By screening with 32P-(A)+RNA from male and female flies, respectively, we were able to isolate a set of 100 cDNA clones which showed a positive hybridization signal for RNA from female flies. These clones have been rescreened with RNA isolated from fat body of two day old male and female flies. We obtained four positive cDNA clones. Isolation of the corresponding genomic sequences, construction of the physical map and comparing it with the restriction maps published by Barnett et al. (1) led us to conclude that we had isolated the genes coding for two of the three known yolk protein precursors (vitellogenins), YP I and YP II. The sequence of the YP I gene was determined. It gives rise to a protein of 48 700 dalton MW which might be cleaved to a MW of 46 700 during transport. The coding sequence is interrupted by a single intron of 75 bases in length. The proposed leader sequence starts at a region homologous to six heat shock gene sequences at the site of initiation of transcription, suggesting the existence of an 11 bp cap specific consensus sequence for Drosophila melanogaster.