Aviva Zapinsky

Biological Sciences
“Ribosomal Biosynthesis after Repression of Specific Ribosomal Protein Genes”

Aviva Zapinsky

Composed primarily of rRNA, ribosomes also contain ribosomal proteins as an integral part of their structure. Ribosomes synthesize proteins, translating the mRNA sequence into amino acid chains. Ribosomal proteins are themselves translated in the cytoplasm and then transported into the nucleus – to the region known as the nucleolus, where they are incorporated into the ribosomal structures by binding to the rRNA. The synthesis of the two ribosomal subunits requires production of rRNA, 79 ribosomal proteins, and about 200 assembly factors. Disruption of the synthesis of any components leads to nucleolar stress, where the ribosome assembly becomes unsuccessful and the cell cycle gets interrupted. Using yeast as a model organism, I want to determine how the repression of one of the ribosomal proteins affects the fate of ribosomal proteins that are synthesized. I am studying whether during the repression of specific ribosomal proteins other ribosomal proteins are still transported to the nucleus, or whether they remain in the cytoplasm. If the transport of ribosomal proteins remains functional, I would like to determine whether the ribosomal proteins are incorporated into the ribosomal particles and whether these incomplete ribosomal particles are exported to the cytoplasm. Using a yeast strain in which the ribosomal protein L43 is expressed under a galactose promoter and therefore repressed when grown in glucose media, I inserted a GFP-tagged L25 gene under the control of an inducible beta-estradiol promoter. The GFP-tagged L25 protein can be differentiated from the native L25 that is being expressed constitutively. Thus, I can follow the L25-GFP that was induced after the repression of L43 by microscopy and determine whether it does get transported into the nucleus and out again. Incorporation of the tagged protein can be determined by sucrose gradient centrifugation and Western analysis of the gradient fractions. These studies will lead to a greater understanding of the stress response, and the connection between nucleolar stress and the cell cycle.

Who is your mentor for your research, scholarship, or artistic project? How did you arrange to work with this person?
My PI is Dr. Lindahl in the Biological Sciences department; however, I work very closely with a graduate student Md. Shamsuzzaman, Shams. Shams was my TA for Bio 141 in my freshman year, and at the end of the semester he asked me if I was interested in research. I was, and I was interested in the project that he was working on, so I began to work on my project.

Do you get course credit for this work?
Yes, I do. You can enroll in the class Bio 499 (or Bio 499H, if you are in the honors college) and get anywhere between 1 and 4 credits. But you have to work the corresponding amount of time in the lab, so one credit is about 4 hours of work per week.

How much time do you put into it?
It really depends on the semester, and the number of other classes that I am taking at the time, but I work anywhere between 5 and 15 hours a week in the lab. It also depends on the week, and which experiments I am working on just then – some experiments are definitely more time consuming than others.

What has been the hardest part about your research?
The hardest part about research is when things do not work. That’s research – 95% of the time you did all that work for nothing, and it gets really frustrating. But that 5% of the time when your experiments work, it’s always really rewarding.

How does your research relate to your work in other classes?
Since I am a biology major, and I do research in a biology lab, many of the procedures and experiments that we are doing in the lab are discussed classes like genetics and cell bio. Working in the lab gave me an edge in those classes.

What else are you involved in on campus?
I write for the school newspaper, The Retriever Weekly, since I am a writing minor. In addition, I am a member of the fencing club, and a tutor for the Chemistry Tutorial Center.

What is your advice to other students about getting involved in research?
Really the most important thing to getting involved with research is personal contact with professors and graduate students. If you email a professor whose research you are interested in, they very often can either find you a place in their lab, or ask a different professor with similar research if they have a place. The professors at UMBC are very open to undergraduate research, and that’s one of the great things about UMBC.


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