Sex-, tissue-, and stage-specific expression of a vitelline membrane protein gene from region 32 of the second chromosome of Drosophila melanogaster.

This study isolated cDNA clones from egg-chamber and adult female Drosophila cDNA libraries using as probe a DNA fragment from a 200-kb "chromosome walk" in region 32E of the second chromosome of D. melanogaster. The present authors believe that these clones correspond to a new vitelline membrane protein (VMP) gene because 1) cDNA clones in Northern blots identify a transcript expressed in a tissue- and stage-specific manner: stage 10 egg-chambers; 2) the sequence of cDNAs and of the genomic subclone shows homology with the other VMP genes that have been identified to date; 3) the amino acid composition of the translational product has the high content of proline and alanine characteristic of VMPs. Two aspects emerging from this study are worth stressing: 1) the presence of a hydrophobic domain that is highly conserved in all the VMP genes; and 2) the particularly narrow period of expression of the isolated gene, which could be related to the mechanism of vitelline membrane assembly.