About me
A Behavioral Screen for Genes Required for Blue Light Avoidance in Drosophila
Location: 50
Mentor: Dr. James Baker
When given a choice between red and blue light, adult flies have been found to robustly avoid blue light. Prior molecular/genetic studies of this avoidance indicate that the detection of blue light in this behavior is mediated by novel cellular and molecular mechanisms that rely on neurons found in the fly abdomen and on a previously undiscovered transduction mechanism. To further characterize this behavior, we have established a new assay that takes minutes to conduct and allows us to screen several genetic combinations in a short time. As a test of this approach, we crossed flies lacking the key blue-light sensitive protein rhodopsin-7 (rh7) to flies lacking the channel previously shown to play a role, painless (pain). The resulting flies are trans-heterozygous for pain and rh7 and are worse at avoiding blue light than wild type. To date we have tested dozens of genes for similarly diminished responses when in trans to rh7, mostly with negative results. Recently, we have identified two new candidate genes via this screen, tmem63 and cullin-4 (cul4). We have tested mutants in these two loci, initially as trans-heterozygotes with rh7 and then as homozygotes and find that in both instances these mutants have diminished blue light avoidance. We are conducting follow up studies to determine where and when these genes are expressed. We show that the cul4 gene is expressed in glial cells that support the abdominal blue-light sensitive neurons, reinforcing our finding that CUL4 is required for the avoidance of blue light.
