558 / 2019-03-15 22:39:25

Blue-light induces selection of transcription start sites to ensure expression of light responsive genes

Blue light, Transcription start site, CAGE, NMD, Ribosome profiling

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Light is an important environmental signal for plant development. Expression of many light-regulated genes are induced by light irradiation. To understand light regulation of genes we performed Cap-Analysis Gene Expression (CAGE) profiling to determine mRNA transcription start site (TSS) precisely. We analyzed genome wide TSS profiles in Arabidopsis seedling by Blue-light exposure. Many light regulated genes have upsteam open-reading frame (uORF) in their 5’ non-coding region. uORFs often function as translation inhibitors caused by NMD and ribosome stalling. TSS located downstream of uORFs in 220 genes is enhanced by BL exposure. This kind of regulation is found in HY5 and HYH. Translation efficiencies of the genes with enhanced usage of these TSSs increased upon BL exposure. These results indicate BL controls gene expression by choosing downstream TSS to escape uORF-mediated inhibition and ensure high expression of light-inducible genes.