Multiple elements controlling the expression of wheat high molecular weight glutenin paralogs

Abstract

Analysis of gene expression data generated by high-throughput microarray transcript profiling experiments coupled with cis-regulatory elements enrichment study and cluster analysis can be used to define modular gene programs and regulatory networks. Unfortunately, the high molecular weight glutenin subunits of wheat (Triticum aestivum) are more similar than microarray data alone would allow to distinguish between the three homoeologous gene pairs. However, combining cDNA expression libraries with microarray data a co-expressional network was built that highlighted the hidden differences between these highly similar genes. Duplex clusters of cis-regulatory elements were used to focus the co-expressional network of transcription factors to the putative regulatory network of Glu-1 genes. The focused network helped to identify several modules of transcriptional gene programs in the endosperm. Many of these programs demonstrated a conserved temporal pattern across the studied genotypes, however few others showed variance. Based on this network, transient gene expression assays were performed with mutated promoters to inspect the control of tissue specificity. Results indicated that the interactions of the ABRE│CBF cluster with distal promoter regions may have a dual role in regulation by both recruiting the transcription complex as well as suppressing it in non-endosperm tissue. A putative model of regulation is discussed.

A novel NAC family transcription factor SPR suppresses seed storage protein synthesis in wheat

“…Previously identified regulatory elements of SSP genes were always distributed within a region <500 bp upstream of the start codon (Forde et al ., 1985; Halford et al ., 1989; Hammond‐kosack et al ., 1993; Muller and Knudsen, 1993). However, regulatory elements were also predicted recently in the regions much far from 500 bp upstream of the start codon of HMW‐GS and LMW‐GS genes (Juhász et al ., 2011; Makai et al ., 2015; Ravel et al ., 2014). Whether the cis ‐element 5′‐CANNTG‐3′ predicted here in the regions 500–2000 bp upstream of the start codon was involved in the regulation of SSP genes still needs more evidence.…”

High-Molecular-Weight Glutenin Subunits: Genetics, Structures, and Relation to End Use Qualities

“…The mechanism that regulates HMW-GS expression remains largely unclear [47]. Some conserved cis-acting elements related to the expression of storage proteins have been identified in HMW-GS gene promoters [47][48][49][50]. To date, storage protein activator (SPA), a member of the basic leucine zipper (bZIP) family, has been identified to play a key role in the regulation of wheat grain storage protein synthesis [51][52][53][54][55].…”

Clustered Transcription Initiators and Expression of HMW‐GS Genes in Wheat Endosperm

“…The HMW-GSs, together with the low-molecular-weight glutenin subunits (LMW-GSs), form glutenin macropolymers (GMPs) by intermolecular disulfide bonds to confer dough viscoelasticity (Payne et al, 1987). Some cis-elements, e.g., the TATA box, Prolamin box, RY repeat, and Skn-1 element, have also been predicted in the promoter of HMW-GS genes, which are usually found 1 to 2 kb upstream of the translation start codon or even farther Ravel et al, 2014;Makai et al, 2015). The nucleotide sequences, varying from hundreds to thousands nt upstream of the translation start codon, have a function in promoting the expression of HMW-GS or reporter genes in gramineae endosperm (Barro et al, 1997;He et al, 1999He et al, , 2005Lamacchia et al, 2001;Norre et al, 2002;Tosi et al, 2004;Furtado et al, 2009;Liu et al, 2011).…”

“…The nucleotide sequences, varying from hundreds to thousands nt upstream of the translation start codon, have a function in promoting the expression of HMW-GS or reporter genes in gramineae endosperm (Barro et al, 1997;He et al, 1999He et al, , 2005Lamacchia et al, 2001;Norre et al, 2002;Tosi et al, 2004;Furtado et al, 2009;Liu et al, 2011). Some cis-elements, e.g., the TATA box, Prolamin box, RY repeat, and Skn-1 element, have also been predicted in the promoter of HMW-GS genes, which are usually found 1 to 2 kb upstream of the translation start codon or even farther Ravel et al, 2014;Makai et al, 2015). However, little is known about the transcription initiators and their roles in HMW-GS gene expression.…”