GCN Sensitive Protein Translation in Yeast

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Live Poster Session: Zoom Link
Thursday, July 30th 1:15-2:30pm EDT

Jack Kwon
Jack Kwon

Jack Kwon is a rising senior (’21), and he will be living in 76 Lawn Ave. He is from Suwanee, Georgia and graduated from Lambert High School in the spring of 2017. He loves to play Ultimate Frisbee and is part of the Wesleyan Men’s Ultimate Frisbee team: Nietzsch Factor. He also loves listening to music, learning new things in the field of molecular biology, and spending time with family and friends. He plans to double major in MB&B (Molecular Biology and Biochemistry) and CIS (College of Integrative Sciences) and then complete the BA/MA program at Wesleyan.

Carol Dalgarno
Carol Dalgarno

Carol Dalgarno is a rising senior (’21) double majoring in Molecular Biology and Biochemistry and Science in Society. She grew up in Brookline, Massachusetts and graduated from Brookline High School. Outside of coursework, Carol enjoys working as a peer tutor, singing in the a cappella group Onomatopoeia, and hiking. After graduation she plans to apply to Biomedical Sciences PhD programs and pursue research with clinical applications.

Abdelrahman Elsayed
Abdelrahman Elsayed

Abdelrahman Elsayed is a rising senior (’21) from Brooklyn, NY, where he graduated from NYC Lab Highschool for Collaborative Studies. Coming from an immigrant family, he has spent much of his life living in Cairo, Egypt and NYC. He studied abroad in Kyoto, Japan during the Spring 2020 semester. His interests are learning about different cultures, hanging out with friends, and engaging in cultural clubs such as the Middle Eastern Student Union. He is a computer science major and CEAS minor. He hopes to use his interdisciplinary studies at Wesleyan to pursue unique opportunities in the tech field.

Abstract: Our research is focused on elucidating the functional significance of a ‘GCN’ 3-nucleotide periodicity observed in protein coding open reading frames (ORFs). GCN is overrepresented in the initial codons of ORFs (the ramp region), particularly in highly expressed genes. The Weir lab has observed through Molecular Dynamics (MD) simulation that there is an interaction surface located in the mRNA entrance tunnel of the ribosome near the A site decoding center. This CAR interaction surface consists of 16S/18S rRNA C1054, A1196 (E. coli numbering), and yeast ribosomal protein Rps3 R146. Further investigation of this interaction surface revealed that there is an mRNA-ribosome interaction (through hydrogen bonding) between the CAR interface and GCN in the mRNA +1 codon which is the codon about to enter the A site. We hypothesize that this mRNA-ribosome interaction can lead to modulation in protein translation, and under different conditions (e.g. stress conditions) or sequence contexts, the mRNA-ribosome interactions can serve as a mode of regulation for protein translation. Previous wet lab experiments have shown that mutations that deviate from the GCN periodicity in the ramp region lead to changes in protein expression levels. The western blot analysis was followed up with mRNA abundance and protein stability assays to ensure that the mutations did not significantly alter overall mRNA abundance levels and protein stability which could both affect steady-state protein expression levels. We similarly made mutations in the mRNA in MD simulations of the ribosome to observe how the mRNA-ribosome interactions may change. Specifically, we observed that deviating from GCN led to decreased interactions (through hydrogen bonding) between the CAR interface and the mRNA +1 codon. Indeed, A-rich and CGN codons show particularly weak CAR interactions. We hypothesize that the codon identity and the degree of conformance to the GCN periodicity of the codons in the ramp region determine the level of mRNA-CAR interaction and hence the level of protein expression.

2020_Wet_Lab_Poster-Jack-Kwon

Live Poster Session: Zoom Link
Thursday, July 30th 1:15-2:30pm EDT

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