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A cis-regulatory sequence from a short intergenic region gives rise to a strong microbe-associated molecular pattern-responsive synthetic promoter

Lehmeyer, Mona, Hanko, Erik K. R., Roling, Lena, Gonzalez, Lilian, Wehrs, Maren, Hehl, Reinhard
Molecular genetics and genomics 2016 v.291 no.3 pp. 1155-1165
Arabidopsis thaliana, gene expression, genetically modified organisms, intergenic DNA, leaves, mutation, nucleotides, reporter genes
The high gene density in Arabidopsis thaliana leaves only relatively short intergenic regions for potential cis-regulatory sequences. To learn more about the regulation of genes harbouring only very short upstream intergenic regions, this study investigates a recently identified novel microbe-associated molecular pattern (MAMP)-responsive cis-sequence located within the 101 bp long intergenic region upstream of the At1g13990 gene. It is shown that the cis-regulatory sequence is sufficient for MAMP-responsive reporter gene activity in the context of its native promoter. The 3′ UTR of the upstream gene has a quantitative effect on gene expression. In context of a synthetic promoter, the cis-sequence is shown to achieve a strong increase in reporter gene activity as a monomer, dimer and tetramer. Mutation analysis of the cis-sequence determined the specific nucleotides required for gene expression activation. In transgenic A. thaliana the synthetic promoter harbouring a tetramer of the cis-sequence not only drives strong pathogen-responsive reporter gene expression but also shows a high background activity. The results of this study contribute to our understanding how genes with very short upstream intergenic regions are regulated and how these regions can serve as a source for MAMP-responsive cis-sequences for synthetic promoter design.