Lord of the Flies

Hi! My name is Caitlin Burk. I'm going to be a senior at Durham Academy next year, and I'm working with Drosophila (fruit fly) genetics in Dr. Dan Kiehart's lab in the French Family Science Center. My lab is interested in (among other things) myosin, a motor protein, and dorsal closure--when the fly embryo closes up on the dorsal side (time lapse video here, it's the one on the left).

The first few days in the lab have been pretty fun. Ruth Montague, one of the other people who works in the lab, has been showing me the ropes. I have learned to change fly cages (to collect embryos), quarantine flies (to prevent mites), to collect virgins (females that have already mated can store sperm from multiple males, and this can result in undesired offspring), and make slides for the imaging microscope. When you make a slide, the embryos, which look like clearish-white hot dogs, have to all be oriented dorsal side up in nice little lines. This can be hard because a) it's hard for me to tell which side is the dorsal one and b) the wet embryos are slippery, on agar, very small (2 lines of 6 embryos is less than 1/4 square cm), and I'm using a probe with an unsteady hand. I'm getting better though. One thing I think is interesting is that on the slides, the embryos are in halocarbon oil. They can still breathe in the oil, and are alive when you look at them under (over?) the confocal microscope. On the scope, you can view your slides in two ways: 1) normally. 2) you can turn on the laser attatched to the microscope and look at the embryos on a computer linked to a camera on the scope. Some embryos have transgenes, or genes that have been inserted by a scientist, that tag myosin with GFP (green fluorescent protein). The laser excites these proteins, and the camera has a lens that can show the fluorescence (if you looked through the microscope yourself, the laser would zap your eyes). One other thing I learned: When scientists discover a fly gene, they can name it whatever they want. There are genes called armadillo, spaghetti squash, hedgehog, etc.

Today I went to my first lab meeting, where Vinay, a grad student, presented the work he's been doing on the formation of fly hair. It was a little over my head, but I was able to actually understand most of what he was saying for about 45 minutes and then asked questions later. I also finally got to meet Dr. Kiehart, who got stuck coming back from Montreal yesterday. We planned out my project, which will deal with the brightness of the fluorescence of different GFP-flies. Fluorescence differs between different flies because of the position of the transgene. In one line of flies, the gene may have inserted itself in a very thick and crowded part of the DNA. Transcription enzymes will have a hard time getting to this section, and the gene won't be expressed very much (dim fluorescence). If in another line of flies, the gene inserts itself in a more spread out and accessible part of the genome, it will be more expressed (bright fluorescence) because the RNA polymerase can more readily transcribe the gene.

Anyway, I have to go read a paper to get ready for my project. More information my project--and why it's helpful for my lab--later (and hopefully pictures too!).