Analysis of OS-E and OS-F expression in Drosophila melanogaster using GAL4 transgenes with green fluorescent protein
The genes OS-E and OS-F are expressed in the sensory nerve network of D. melanogaster's antennae and maxillary palps and are putative odorant-binding proteins. A transgenic construct used GAL4 to drive production of GFP in tissues where the gene of interest was being transcribed. Each gene drove production of GFP at a different time in pupal development. OS-E was found to fluoresce in sensory structures at 60 hours after pupation and OS-F fluoresced at 90 hours. Real-time quantitative PCR was used to study flies without gene insertions to determine the molecular nature of the expression of the two genes and consequently whether the developmental model shown by GFP was indicative of a natural process. PCR data were taken from a developmental time period when OS-E/GFP production was active and OS-F/GFP was not; these were compared to samples from adult flies. Concentrations of OS-E mRNA and OS-F mRNA were found to be surprisingly similar, indicating either that the GFP model is inaccurate, or that problems with the PCR reactions caused misrepresentative results.