Student Research at Duke

The poster is sort of the fruit of our eight weeks of labor, but it goes so much beyond that. To recapitulate some of the finer moments…

Throwing a surprise birthday party for my P.I., aka Nina Sherwood, when she was so determined to not let anyone know that her birthday was coming up (;-)).

I, coercing the people in my lab to dress up for harry potter, which they did bemusedly. haha.. thanks guys!

Left to right: Chris (sitting), Daniel (standing in the back), Fang (wearing my ridiculous sweater), Emily (the Tall One), Lisa (a good Snape), and me (Prof. Trelawney, the “right old fraud).

Perfecting my larval dissection skills (still in the makings..)

Asking billions of questions, which no pictures can demonstrate. Going to inspiring and thought provoking lectures, to realize that science goes beyond bench work and can have an enormous impact on society. Working with really cool people, learning to think critically, game nights every thursday with lab mates, and all that jazz.

Entire lab: Front Row- Nina Sherwood and Lisa Pang. Middle: Fang Du (mentor!) and I. Last: Chris, Emily Odowski, Daniel, and Michael. CHECK OUT THE BUTTONS!!!

Last of all.. I couldn’t resist. Lisa, aka Severus Snape, and I/me as Prof Trelawney

Question: What do you picture as your future career?

Answer: It’s a tough question. I know what my interests are, but they are dispersed and varied. I do want to have an exciting career. Something that’ll keep me motivated and occupied for more than the 40 hours/week. Science is extremely exciting, especially when you figure out something really cool, never been known before. I also like working with people. I like videocameras. I don’t know the answer to the question yet, but I feel like I have some time to explore. I know my interests, so I have a starting point. After working for 6 weeks in a lab now, I’m pretty sure research is something I would like to continue. But other than that, I still have a lot of stuff to fill in my slate.

Last week in the lab was exciting and tedious. Exciting because we’re starting to accumulate some results. This is going to require a little explaining. So, you’ve already heard my on and ons about spastin. The research project I’m working on involves testing flies with mutated copies of human spastin with a drug called Vinblastine. Vinblastine has been shown to rescue flies with mutated copies of Drosophila spastin, so we’re testing it again, using both behavioral and molecular assays, but using human mutations.

A brief and hopefully clear summary. The vinblastine flies are starting to hatch and I have been counting flies in the different genotypes of the cross (we crossed Human mutated spastin flies with a 301 stock–to be explained later). Some fly genotypes appear in larger number than others. We’re checking to see if vinblastine would allow more flies to eclose that do not normally eclose in a high frequency. Next week will involve a bit of both molecular and behavioral work. Molecular– we’re going to be looking at dissected vinblastine larvae under the confocal microscope. Behavioral– comparing eclosion rates between control and vinblastine flies.

Now on to balancers. Balancers, or balancer chromosomes, make the work of geneticists so much easier. Defined simply, balancers chromosomes are messed up chromosomes that have so many mutations that they cannot recombine. There are known sets of balances for each of the four pairs of chromosomes in a Drosophila. So, when you cross a fly, you can accurately predict the genotype of its progeny. Because if a progeny didn’t get a balancer with a specific marker, then you know that it got the mutated copy. Some other properties of balancers– have a couple of dominant and recessive markers and homozygous lethality. If you get two pairs of balancers (e.g. Tm6b/Tm6b), the zygote will not survive–. Tm6b is a commonly used balancer. It’s on the third chromosome in Drosophila and is characterized by a tubby larvae and humeral mutation (the fly has a hairy armpit).

To make sure we got the desired genotype for our progeny, we crossed the vinblastine fly with a 301 balancer stock line (with Tm6b, since spastin gene is also found in the third chromosome of flies).

My modern version of an ode.

I am one of those people who understands things better with pictures and practical applications. I think the correct term is visual learner. If I only relied on words to explain my research project to you, I think I would end up making more than one person confused (including me).
So check out the video below. Yes, at first glance, it is only a bunch of flies, but look a little more closely…

Link –
http://biology.plosjournals.org/archive/1545-7885/2/12/supinfo/10.1371_journal.pbio.0020429.sv001.mov
–(Courtesy of Sherwood et al., 2004)

The first group of flies are the wild type flies. They can walk, jump, and fly normally. They are really fast, so sometimes all you see is a blur. The next batch, titled spastin-null flies, are different. Why? Well, you can actually see them. If you look closely, you can see that they have trouble walking. They have weak legs (especially their hind legs) and do not fly very well. The third batch are the happy flies–Rescued Flies.

So, what different about the flies? The first set have a normal set of SPG4 gene, which encodes for the protein spastin. The second set have no spastin. The third group of flies have the human version of the spastin gene (“Rescued Flies”).

What exactly is spastin’s role and function in the human body? Put simply, spastin severs microtubules. It has been found that spastin plays an important role in ensuring proper synapsing of motor neurons. When a mutation in the spastin gene hinders its function, stable microtubules accumulate in the CNS axons, and motor neurons cannot communicate properly. Mutations in the spastin gene account for almost 40% of AD-HSP (Autosomal Dominant Hereditary Spastic Paraplegia) cases in humans. AD-HSP in humans is characterized by weakness of legs and bilateral spasticity. Patients exhibit an abnormal gait and oftentimes lose the ability to walk as the disease progresses.

When Dr. Sherwood explained this to me, she used videos as well (good choice ). First she showed me a video of HSP patients and then the fly video. It was as if a field of lightbulbs had alighted, as well as thousands of questions. One neat aspect of science is being able to tackle a problem in so many creative ways, such as by creating different models to understand a question better. Our lab creates fly models to mimic the different mutations found in the human SPG4 gene. Even if fly models are not entirely perfect, gene conservatism between Drosophila and humans is estimated to be around 60% (including human disease genes). So, there is good correlation between human and fly phenotypes.

It’s pretty cool to see theoretics mimic reality.

When I first started working in lab, I wasn’t afraid of bugs, but I wasn’t fond of them either. One day when I was walking outside, just strolling peacefully around a trail on a fine spring day, a bug starts to attack/follow me. And it doesn’t give up either. It keeps bumping into me and chases me around the trail, probably laughing devilishly in its little brain about my helplessness. So, in addition to doing some cool research, I entered Sherwood lab with a diabolical plan to have my revenge on the annoying bugs. Since I don’t have pictures of my lab yet, I will do my best to explain our work area in words. Imagine a lot of shelves with the typical labby stuff—buffers and solutions and chemicals. Then picture tables and fume hoods covered with hundreds of vials of neatly labeled Drosophila flies…and you have my lab. Every lab has some sort of routine maintenance thing that is not fun, but just has to be done. For our lab, it is transferring those hundreds of vials of Drosophila into other hundreds of vials of fresh food. In my first week, I might have transferred about 500 vials (not bragging or anything). It took some time to get used to; especially since the first one was a fiasco. Have you ever seen a picture of a cute kid releasing a jar of butterflies, with a serene expression of his face? Mine still frame of my first vial would be me staring in terror at the fruit flies escaping to freedom (some bumping in my face, some meeting the wrath of my deadly hands). Don’t worry, the situation was under control in a few seconds—I stuffed cotton down the vial.

After swatting a couple of flies in lab, I felt like I was avenged. And you know what (here comes the twist in the story), I began to feel sorry for the little flies. They are actually quite cute. You wouldn’t believe this unless you have seen them closely under a microscope. And they make excellent model organisms; there has been so much research published about the husbandry and genetics of fruit flies (just visit www.flybase.com). They do their jobs well (which is remaining healthy and mating constantly). They are excellent for the type of research done in Sherwood lab, and the type of research I will continue/initiate in the next.. oh seven weeks. I think the next paragraph should begin the details of my research project, but I’ll hold off on that until next post