Seminar "Light controls protein localization through phytochrome-mediated alternative promoter selection in Arabidopsis"

Title: "Light controls protein localization through phytochrome-mediated alternative promoter selection in Arabidopsis"

Speaker: Prof. Tomonao Matsushita (Faculty of Agriculture, Kyushu University, Japan)

Abstract:

Biological complexity relies on the diversity of the proteome, which can be increased beyond the number of genes. With alternative promoter usage, multiple pre-mRNAs are transcribed from a single gene. Alternative promoter selection, evident in various organs, tissues, and cancer cells, can affect translational efficiency or stability of mRNA or alter the N-terminal lengths of the encoded proteins. However, the impact of this mechanism on the proteome and whether it is positively exploited in normal organismal responses remain unclear. Recently we found that the plant photoreceptor phytochrome induces genome-wide changes in alternative promoter selection in Arabidopsis (Ushijima et al., Cell 2017). Through this mechanism, protein isoforms with different N-termini are produced that display light-dependent differences in localization. Our results demonstrate that phytochrome controls alternative promoter selection to modulate protein localization, thereby allowing plants to adapt to light environments. Furthermore, this study strongly suggests that alternative promoter usage represents another ubiquitous layer of gene expression regulation in eukaryotes that substantially contributes to the functional diversification of the proteome. Now we are trying to elucidate the molecular mechanisim of this phytochrome-mediated alternative promoter selection and the recent progress will be presented and discussed.