The Mechanism of GT Element-mediated Cell Type-specific Transcriptional Control

Abstract

Promoter studies have revealed that sequences related to the GT-1 binding site, known as GT elements, are conserved in plant nuclear genes of diverse functions. In this work, we addressed the issue of whether GT elements are involved in cell type-specific transcriptional regulation. We found that the inactivation of GT-1 site-mediated transcription in roots is correlated with the absence of the GT-1 binding activity in root extracts. In addition, the mutation of the related GT-1 (from the pea rbcs-3A) and the S1F (from the spinach rps1) sites resulted in an increase of their transcriptional activity in roots that contain a distinct GT element-binding factor, referred to as RGTF. Although specific to GT elements, RGTF has a different sequence requirement and a lower sequence specificity than GT-1. Interestingly, RGTF has a higher binding affinity to the mutant GT-1 and S1F sites than to the wild-type sequences. This correlation suggests that RGTF may have some role in transcriptional regulation in roots. Furthermore, root cellular protein extracts contain an inhibitory activity that prevents GT-1 from binding to DNA. This helps to explain the absence of the GT-1 binding activity in roots in which the gene of GT-1 is expressed. Together, these data suggest that the cell type-specific transcription modulation by GT elements is achieved by using two different strategies.

Isolation and characterization of a copalyl diphosphate synthase gene promoter from Salvia miltiorrhiza

“…1, Tab. 2) [31][32][33]. However, the other potential cis-active elements associated with the response to light and auxin as well as the regulation of the circadian clock were also found, without the corresponding trans-factors [34][35][36][37][38][39].…”

Light Induces Peroxisome Proliferation in Arabidopsis Seedlings through the Photoreceptor Phytochrome A, the Transcription Factor HY5 HOMOLOG, and the Peroxisomal Protein PEROXIN11b

“…We found a total number of 19 putative LREs (Supplemental Fig. S3), including seven GATA boxes (Lam and Chua, 1989), six GT1 boxes (Villain et al, 1996), three I boxes (Giuliano et al, 1988), one AE box (Park et al, 1996), one ATCT motif (Conley et al, 1994), and one GGATAA element (Tepperman et al, 2001). GATA, GT1, and I boxes are cis-elements commonly existing in light-regulated promoters and shown to be essential for light-controlled transcriptional activity (Tobin and Kehoe, 1994;Terzaghi and Cashmore, 1995;Millar and Kay, 1996).…”

Thousands of Cis-Regulatory Sequence Combinations Are Shared by Arabidopsis and Poplar

“…SORLREP5AT and SORLREP2AT are known to be phyA-repressed motifs (Hudson and Quail, 2003) and phyA is critical for red or far-red light photoreceptor activities (Dehesh et al, 1993). BOX1PVCHS15 is known to be bound by GT-1 (Villain et al, 1996) and GT-1 is also related to red light and far-red light response (Gilmartin and Chua, 1990;Escobar et al, 2004). Thus, this cis-regulatory sequence combination M3121 is important for the red or far-red light photoreceptor activity and all three cis-regulatory sequences in this combination may interact to regulate their 187 target genes.…”