Light Regulation of Nuclear Photosynthetic Genes in Higher Plants

Light can modulate development and differentiation of the vital photosynthetic organelle, chloroplast, by photomorphogenetic mechanisms involved in regulating transcription of various photosynthetic genes encoded by nuclear genome. The nuclear genes encode majority of proteins involved in photosynthesis. After perception, light signal is transduced via signaling intermediates, which have been identified using various approaches. These signaling components can either directly influence the binding of light regulatory trans-acting factors to cis-acting elements present in a photosynthetic gene promoter or modulate their activity by various means to facilitate transcription in response to light. Some cis-acting elements show a high degree of conservation among photo-responsive nuclear genes in plants and have been designated as light regulatory elements (LREs). The gene regulation seems to involve interplay of several cis-acting elements and regulatory factors. Additional information available about the post-transcriptional mechanisms responsible for light-regulated expression of photosynthetic genes suggests the importance of these levels in regulation biology.