LIGHT-REGULATED TRANSCRIPTION

This review focuses on light regulation of transcription, from Light perception to changes in transcription, with an emphasis on regulatory elements in the promoters of light-regulated genes and proteins that bind to them. The abundance of over 100 mRNAs is regulated by light, and at least three photoreceptors influence transcription, but the importance of each photoreceptor may vary from gene to gene. Light-regulated promoters are composed of ubiquitous regulatory elements; the specific combination of elements appears to make a promoter light-regulated, and these combinations vary widely. Numerous proteins that bind to elements in light-regulated promoters have been identified and many have been cloned, but no cloned gene has been unequivocally assigned a function in light-regulated transcription, Substantial progress has been made in identifying steps in signal transduction from light perception to transcription, but these steps have yet to be assembled into complete pathways.