Journal Article

Regulated <i>AtHKT1</i> Gene Expression by a Distal Enhancer Element and DNA Methylation in the Promoter Plays an Important Role in Salt Tolerance

Dongwon Baek, Jiafu Jiang, Jung-Sung Chung, Bangshing Wang, Junping Chen, Zhanguo Xin and Huazhong Shi

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 52, issue 1, pages 149-161
Published in print January 2011 | ISSN: 0032-0781
Published online November 2010 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcq182
Regulated AtHKT1 Gene Expression by a Distal Enhancer Element and DNA Methylation in the Promoter Plays an Important Role in Salt Tolerance

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Through sos3 (salt overly sensitive 3) suppressor screening, two allelic suppressor mutants that are weak alleles of the strong sos3 suppressor sos3hkt1-1 were recovered. Molecular characterization identified T-DNA insertions in the distal promoter region of the Arabidopsis thaliana HKT1 (AtHKT1, At4g10310) in these two weak sos3 suppressors, which results in physical separation of a tandem repeat from the proximal region of the AtHKT1 promoter. The tandem repeat is approximately 3.9 kb upstream of the ATG start codon and functions as an enhancer element to promote reporter gene expression. A putative small RNA target region about 2.6 kb upstream of the ATG start codon is heavily methylated. CHG and CHH methylation but not CG methylation is significantly reduced in the small RNA biogenesis mutant rdr2, indicating that non-CG methylation in this region is mediated by small RNAs. Analysis of AtHKT1 expression in rdr2 suggests that non-CG methylation in the putative small RNA target region represses AtHKT1 expression in shoots. The DNA methylation-deficient mutant met1-3 has nearly complete loss of total cytosine methylation in the putative small RNA target region and is hypersensitive to salt stress. The putative small RNA target region and the tandem repeat are essential for maintaining AtHKT1 expression patterns crucial for salt tolerance.

Keywords: AtHKT1; DNA methylation; Enhancer element; Gene regulation; Salt stress

Journal Article.  7592 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.