On the molecular mechanism of gypsy-induced mutations at the yellow locus of Drosophila melanogaster.

Abstract

We determined the nucleotide sequence of genomic DNA corresponding to the yellow gene. The limits of the transcribed region were deduced from sequence analysis of yellow larval and pupal cDNA clones. The yellow transcription unit is simple, composed of two exons which are processed identically in both developmental stages into a mRNA of 1990 bp. The predicted yellow protein has a mol. wt of 60,752 daltons and appears to be a secreted protein having a structural function and not an enzymatic role in pigmentation. We also characterized the spontaneous mutation y2 and a revertant of this allele to investigate the mutagenic effect of the gypsy element inserted into this locus. Our results show that this transposon is inserted at ‐700 bp and that the y2+ revertant resulted from excision of the gypsy element leaving behind a complete long terminal repeat (LTR). We conclude, therefore, that the gypsy element is neither inserted into a pupal specific intron or regulatory sequence supporting the hypothesis that mutagenesis is a result of transcriptional interference by the gypsy element on the yellow gene.

yellow and ebony Are the Responsible Genes for the Larval Color Mutants of the Silkworm Bombyx mori

“…All mutant proteins disrupted a large part of a major royal jelly protein conserved motif (supplemental Figure 3). Yellow had two potential N-glycosylation sites (Geyer et al 1986;Drapeau 2003) in all three species, and mutated Yellow proteins (except for type 1 of ch k12 mutant) lacked both of these sites (types 2, 3, and 4 of the ch k12 mutant) or one of these sites (ch l11 mutant). These results suggest that a major royal jelly protein conserved motif including two potential N-glycosylation sites is critical for Yellow function.…”

Genomic Organization of gypsy Chromatin Insulators in Drosophila melanogaster

“…Genomic DNA fragments have insulator activity that is dependent on the presence of Su(Hw) and on the number of binding sites for this protein: To test whether genomic DNA fragments containing Su(Hw)-binding sites are able to act as insulators in vivo, we employed an enhancer-blocking assay used extensively to study the gypsy insulator (Geyer et al 1986). In this assay, DNA fragments to be tested for insulator activity are inserted into a plasmid carrying the yellow gene at a position between the wing and body enhancers and the yellow gene promoter.…”

The Ku Protein Complex Is Involved in Length Regulation of Drosophila Telomeres

“…The same two terminal deficiencies as before were like phenotype because the gypsy insulator blocks the interaction between the wing and body enhancers and the y enhancers, it neutralizes the enhancer-blocking activity of the first gypsy insulator, restoring y expression the promoter (Geyer et al 1986;Gause et al 1998).…”