PhD Candidate The Chinese University of Hong Kong Hong Kong, Hong Kong
Body of Abstract: A universal unconventional G-protein, YchF, was involved in defense response modulation and stress tolerance in various organisms such as human, Escherichia. coli, Arabidopsis thaliana, and rice. However, the molecular mechanism of YchF on stress response regulation remains unclear. Components of translation machinery such as ribosomal RNA and ribosomal proteins are some of the known YchF1 interacting partners identified by our laboratory previously, using rice and Arabidopsis as study models. We hypothesized that YchF1 might act as the stress regulator that controls the turnover of the target proteins through regulating the translational activities on ribosomes. In particular, plant ribosomal proteins usually exhibit heterogeneity as multiple ribosomal protein-encoding genes were found in their genome. The association of YchF1 protein on the ribosome might change its composition, and alter the specificity and affinity towards specific groups of mRNA as its bacteria, yeast, and human homologs do. Our current data showed that the YchF1 protein level might alter protein profiles in plants. It is postulated that the specific interaction between YchF1 and ribosome might shape the plant stress responses through translational regulation. To study the effect of YchF1 proteins on the translational landscape, translatomic analysis was done by polysome profiling, and corresponding protein profiles were investigated using the Arabidopsis homologue (AtYchF1) as the study model. AtYchF1 knockdown mutant and AtYchF1 overexpressor were used as the genetic materials to study the dose-dependent effect of the YchF1 level on the translation profile. A mutant form of AtYchF1, with the abandoned ribosomal protein RPS7 interacting ability, was used to study the effect of ribosomal protein RPS7 binding on the functions of AtYchF1. Moreover, Arabidopsis seedlings were subjected to high salinity to induce changes in translational profiles under abiotic conditions. This project aims to delineate the role of YchF1 and clues on the putative translational regulation in plants.