UC San Diego

Translational elongation plays crucial role in mediating the expression of proteins and finally affecting various biological reactions and processes in living organisms. Reversely, the efficiency and rate of translational elongation is commonly regulated by amounts of internal elements, such as special codon or sequences, and external conditions, such as different nutrient conditions. The relevant effects have been well investigated a lot based on transcriptome or proteome analysis and ribosome profiling. Specifically, previous researches commonly identified lessening of protein production and ribosomal loading, which suggest the variation of elongation efficiency or ribosome stalling derived from poor genetic elements or worse nutrient conditions. We have found that, the existence of poly-proline sequence in nuclear-encoded mitochondrial proteins, such as ATP3 and Tim50, shows negative effects in the translation efficiency and the final products, while positive effects in mRNA localization on mitochondria. Since it is well-established that consecutive prolines will result in ribosomal stalling on mRNA, we assumed that the “stalling” may decrease the overall elongation rate, which can be measured and quantified in vivo. In addition, we also intend to monitor the translation variation of Yeast after switching from normal glucose condition to an unfamiliar condition, such different carbon source provide or even nutrient depletion. We finally realized that the translation of Yeasts is going to be impeded after alteration of nutrient supply, then great adaptation to the external “stress” is shown by organisms.