Structural genes of wheat and barley 5-methylcytosine DNA glycosylases and their potential applications for human health
Contributed by Diter von Wettstein, October 15, 2012 (sent for review October 5, 2012)
Abstract
Wheat supplies about 20% of the total food calories consumed worldwide and is a national staple in many countries. Besides being a key source of plant proteins, it is also a major cause of many diet-induced health issues, especially celiac disease. The only effective treatment for this disease is a total gluten-free diet. The present report describes an effort to develop a natural dietary therapy for this disorder by transcriptional suppression of wheat DEMETER (DME) homeologs using RNA interference. DME encodes a 5-methylcytosine DNA glycosylase responsible for transcriptional derepression of gliadins and low-molecular-weight glutenins (LMWgs) by active demethylation of their promoters in the wheat endosperm. Previous research has demonstrated these proteins to be the major source of immunogenic epitopes. In this research, barley and wheat DME genes were cloned and localized on the syntenous chromosomes. Nucleotide diversity among DME homeologs was studied and used for their virtual transcript profiling. Functional conservation of DME enzyme was confirmed by comparing the motif and domain structure within and across the plant kingdom. Presence and absence of CpG islands in prolamin gene sequences was studied as a hallmark of hypo- and hypermethylation, respectively. Finally the epigenetic influence of DME silencing on accumulation of LMWgs and gliadins was studied using 20 transformants expressing hairpin RNA in their endosperm. These transformants showed up to 85.6% suppression in DME transcript abundance and up to 76.4% reduction in the amount of immunogenic prolamins, demonstrating the possibility of developing wheat varieties compatible for the celiac patients.
Data Availability
Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. FM164415.1, JF683316, JF683317, and JF683318).
Acknowledgments
We thank P. Reisenauer and E. Mackenzie and Drs. N. Ankrah, J. L. Ullman, and R. Brueggeman for field and laboratory assistance. This work was supported by National Institutes of Health Grants GM080749-01A2 and 2R42DK072721-02, Life Sciences Discovery Fund Grant 3143956, a Mercator Professorship from the German Research Foundation (to D.v.W.), and Programme of Introducing Talents of Discipline to Universities Project B07017 to Key Laboratory of Vegetation Ecology, Ministry of Education, People's Republic of China.
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Freely available online through the PNAS open access option.
Data Availability
Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. FM164415.1, JF683316, JF683317, and JF683318).
Submission history
Published online: November 26, 2012
Published in issue: December 11, 2012
Keywords
Acknowledgments
We thank P. Reisenauer and E. Mackenzie and Drs. N. Ankrah, J. L. Ullman, and R. Brueggeman for field and laboratory assistance. This work was supported by National Institutes of Health Grants GM080749-01A2 and 2R42DK072721-02, Life Sciences Discovery Fund Grant 3143956, a Mercator Professorship from the German Research Foundation (to D.v.W.), and Programme of Introducing Talents of Discipline to Universities Project B07017 to Key Laboratory of Vegetation Ecology, Ministry of Education, People's Republic of China.
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The authors declare no conflict of interest.
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Structural genes of wheat and barley 5-methylcytosine DNA glycosylases and their potential applications for human health, Proc. Natl. Acad. Sci. U.S.A.
109 (50) 20543-20548,
https://doi.org/10.1073/pnas.1217927109
(2012).
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