Pupal and larval cuticle proteins of Drosophila melanogaster

Abstract

Proteins, soluble in 7 M urea, were extracted from third-instar larval and pupal cuticles of Drosophila melanogaster. Both extracts contain a limited number of polypeptides resolved by one- or two-dimensional electrophoresis. The five major larval proteins have low molecular weights (less than 20000) and are not glycosylated. The major pupal cuticle proteins fall into two size classes: two with apparent molecular weights of 56K and 82K and four with molecular weights between 15K and 25K. The proteins with high apparent molecular weights are glycosylated. In nondenaturing gels, no components of the larval and pupal cuticle extracts comigrate. One-dimensional "fingerprints" indicate that cuticle proteins from these two stages have unique primary structures. Immunological results indicate that the major low molecular weight larval and pupal cuticle proteins are comprised of two families of proteins that share antigenic determinants. The high molecular weight pupal cuticle proteins are immunologically unrelated to the low molecular weight components. We conclude that the pupal and larval proteins are encoded in part by multigene families that have arisen by gene duplication and evolutionary divergence.

Ecdysone regulation of cuticle protein gene expression inDrosophila

“…Low-molecular-weight proteins are also present in extracts from pupal and larval cuticles. In additions, these extracts contain high-molecular-weight and basic proteins [7,12].…”

Structure of O‐glycosidically linked oligosaccharides synthesized by the insect cell line Sf9

“…It has been reported that the cells can incorporate radioactive oligosaccharide precursors into glycoproteins also in the presence of tunicamycin [2,6,7]. Analysis of the monosaccharide composition of glycoproteins synthesized by insect cells have in some cases demonstrated the presence of N-acetylgalactosamine [ 1,2,8]. Other investigators have shown that some glycoproteins isolated from insect cells can be probed with N-acetylgalactosamine specific lectins [ 1,2,9,10,1 I].…”

Synthesis and deposition of PCG‐100, the main pupal cuticle glycoprotein of the medfly Ceratitis capitata

“…Furthermore, the composition of both PCG-100 and PCP-82 oligosaccharides seems to be similar (Silvert et al, 1984;Boccaccio and Quesada, unpublished results).…”

“…Stage-specific, insoluble, insect larval and pupal cuticle proteins (PCP)* that can be extracted with 7 M urea or 1% SDS were previously found to be excellent differentiation markers (Chihara et al, 1982;Skelly and Howells, 1987;Roberts and Willis, 1980; Silvert et al, 1984). The synthesis of these proteins shows temporal regulation (Doctor et al, 1985;Boccaccio and Quesada-All&, 1989a;Kimbrell et al, 1988); this may be related to different cuticular location and/or function (for a recent discussion see Kimbrell et al, 1989).…”