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

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 complementary DNA (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 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. © 2015, Springer-Verlag Berlin Heidelberg

bZIP transcription factors repress the expression of wheat (Triticum aestivum L.) high molecular weight glutenin subunit genes in vegetative tissues

High molecular weight glutenin subunits (HMW GS) represent an important fraction of endosperm-specific seed-storage proteins that provide elasticity to bread dough. Previously, the second cis-regulatory module (CRM2) was found to be one of the most conserved part of HMW GS promoters, which indicated its pre-eminent role in their gene regulation. Here, we observed that deletion of CRM2 from the promoters of the Bx7 and By8 HMW GS genes increased the leakage of their transient expression in wheat leaf tissue. The effect of a VP1, an Myb and an antisense bZIP transcription factor (TF)-binding site, potentially involved in endosperm-specific regulation within CRM2, was then studied. The activity of a Bx7 gene promoter containing a mutant CRM2 with altered VP1 and Myb TF-binding sites, but an intact bZIP TF-binding site, was similarly low to that of the wild type in leaves. Transactivation analysis and EMSA indicated the binding of TFs TabZIP34 and TabZIP115 to the Skn-1 motif GTCAT in CRM2 and the repression of Bx7 and By8 HMW GS gene promoter activity in leaves. TabZIP34 and TabZIP115 may be involved in the downregulation of HMW GS gene expression in vegetative tissues and early-stage endosperm as well its modulation during seed maturation

Az urbanizációs folyamatok áttekintése

Nagykálló város közfeladat-ellátásainak intézményesítései.BSc/BAigazgatásszervezőN.I