Combinatorial interaction of light‐responsive elements plays a critical role in determining the response characteristics of light‐regulated promoters in Arabidopsis

Abstract

SummaryWe have studied the roles of PhyA, PhyB and CRY1 photoreceptors and the downstream light-signaling components, COP1 and DET1, in mediating high-irradiance light-controlled activity of promoters containing synthetic light-responsive elements (LRE). Promoters with paired LREs were able to respond to a wide spectrum of light through multiple photoreceptors, while the light-inducible single LRE promoters primarily responded to a specific wavelength of light. In addition, our results indicate that Cry1 is involved in PhyB-mediated red-light induction of the G-GATA/NOS101 promoter, and that both Cry1 and PhyB are required for effective repression of the GT1/ NOS101 promoter by red or blue light. An interaction between PhyA and PhyB in mediating GT1-GATA/NOS101 promoter light activation was also observed. Furthermore, our data indicate that COP1 and DET1 exert negative control in the dark only on paired LRE promoters but not single LRE promoters. From these results, we conclude that the combinatorial interaction of LREs is essential in determining the ability of light-responsive promoters to be modulated by crucial cellular regulators and to respond to diverse light environments.

Light Regulation of the Arabidopsis Respiratory Chain. Multiple Discrete Photoreceptor Responses Contribute to Induction of Type II NAD(P)H Dehydrogenase Genes

“…GT-1 sites are relatively degenerate cis-elements that are commonly, but not exclusively, associated with light-regulated promoters (Zhou, 1999). The combination of these two elements can form a potent light-responsive core, as a GT-1 and I-box cluster in the pea RBCS-3A gene is required for high-level light regulation (Sarokin and Chua, 1992), and a synthetic tetramer of GT-1 and I-box elements can confer responsiveness to far-red, red, and blue light upon the otherwise non-light-regulated NOS101 promoter (Chattopadhyay et al, 1998). Combinations of GT-1 elements and I-box-like GATA elements are also present in the light-responsive promoters of the genes encoding the H and T subunits of Gly decarboxylase, which catalyzes the first step of photorespiration in the mitochondria (Srinivasan and Oliver, 1995; Vauclare et al, 1998).…”

Sugar-Hormone Cross-Talk in Anthocyanin Biosynthesis

“…In Arabidopsis, the phytochrome (PHY)-interacting transcription factor 3 (PIF3), a bHLH protein, interacts directly with PHYs and positively regulates anthocyanin biosynthesis (Kim et al, 2006;Shin et al, 2007). LONG HYPOCOTYL5 (HY5), a Leu-zipper transcription factor (TF), serves as a point of convergence for phytochrome (PHY) and cryptochrome (CRY) signalings (Gyula et al, 2003), functioning as a positive regulator of anthocyanin biosynthesis (Chattopadhyay et al, 1998). It binds directly to the promoters of early biosynthesis genes (EBGs) such as chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H) and flavonoid 3′-hydroxylase (F3′H), which are common to different flavonoid subpathways, and late biosynthesis genes (LBGs) such as dihydroflavonol 4-reductase (DFR), leucoanthocyanidin oxygenase (LDOX), anthocyanidin reductase (ANR) and UDP-glucose: flavonoid 3-O-glucosyltransferase (UF3GT) (Lee et al, 2007;Shin et al, 2007).…”

The Photomorphogenic Signal: An Essential Component of Photoautotrophic Life

“…First, the LREs identified were not always enough to sustain light regulation. Hence, it was proposed that combinations of different motifs but not multimerisation of single motifs could function as LREs, confirming the complex nature of these regulatory elements (Chattopadhyay et al, 1998;Puente et al, 1996). Second, when the cognate transcription factors were studied in Arabidopsis with available mutants, a direct role in light signal was not evident.…”