|
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
RESEARCH PAPER
Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA
In plants, replication of RNAviruses and RNAfrom highly transcribed transgenes can trigger DNA methylation. These systems accumulate diced small RNA(smRNA) products of double-stranded RNA(dsRNA) precursors, but it is not known which RNAspecies directs methylation. The methylated PAI tryptophan biosynthetic genes in Arabidopsis allow the study of methylation signals for endogenous genes with lower expression levels. The PAI genes are arranged as a tandem inverted repeat plus two singlet genes at unlinked loci. Here we show that the predominant PAI transcript initiates at a novel unmethylated promoter that lies upstream of one of the inverted repeat PAI genes. Suppressed transcription from the upstream promoter using transgene-directed silencing reduces methylation on the singlet PAI genes, but not on the inverted repeat, consistent with an RNAmethylation signal. RNAgel blots detect normal PAI transcripts and dsRNA read-through species, but not diced smRNAs, suggesting that either precursor dsRNAs or subdetectable levels of smRNAs, below the threshold to effectively degrade PAI transcripts, serve as the PAI methylation signal. Thus, the lower expression endogenous gene system allows dissection of a RNA-directed methylation pathway distinct from RNA degradation pathways.
[Keywords: Cytosine methylation; RNA-directed DNA methylation; RNA silencing; small RNAs; dicer]
Received February 7, 2003; revised version accepted June 19, 2003.
1 Present address: Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL 32224, USA.
2 Corresponding author. E-MAIL jbender{at}mail.jhmi.edu; FAX (410) 955-2926.
![]()
CiteULike
Connotea
Del.icio.us
Digg
Reddit
Technorati What's this?
This article has been cited by other articles:
![]() |
M.-B. Wang, C. A. Helliwell, L.-M. Wu, P. M. Waterhouse, W. J. Peacock, and E. S. Dennis Hairpin RNAs derived from RNA polymerase II and polymerase III promoter-directed transgenes are processed differently in plants RNA, May 1, 2008; 14(5): 903 - 913. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Mull, M. L. Ebbs, and J. Bender A Histone Methylation-Dependent DNA Methylation Pathway Is Uniquely Impaired by Deficiency in Arabidopsis S-Adenosylhomocysteine Hydrolase Genetics, November 1, 2006; 174(3): 1161 - 1171. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. L. Ebbs and J. Bender Locus-Specific Control of DNA Methylation by the Arabidopsis SUVH5 Histone Methyltransferase PLANT CELL, May 1, 2006; 18(5): 1166 - 1176. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Fojtova, A. Bleys, J. Bedrichova, H. Van Houdt, K. Krizova, A. Depicker, and A. Kovarik The trans-silencing capacity of invertedly repeated transgenes depends on their epigenetic state in tobacco. Nucleic Acids Res., January 1, 2006; 34(8): 2280 - 2293. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. L. Ebbs, L. Bartee, and J. Bender H3 Lysine 9 Methylation Is Maintained on a Transcribed Inverted Repeat by Combined Action of SUVH6 and SUVH4 Methyltransferases Mol. Cell. Biol., December 1, 2005; 25(23): 10507 - 10515. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Yang, Y.-H. Lee, Y. Jiang, X. Shi, S. Kertbundit, and T. C. Hall A Two-Edged Role for the Transposable Element Kiddo in the rice ubiquitin2 Promoter PLANT CELL, May 1, 2005; 17(5): 1559 - 1568. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Kanellopoulou, S. A. Muljo, A. L. Kung, S. Ganesan, R. Drapkin, T. Jenuwein, D. M. Livingston, and K. Rajewsky Dicer-deficient mouse embryonic stem cells are defective in differentiation and centromeric silencing Genes & Dev., February 15, 2005; 19(4): 489 - 501. [Abstract] [Full Text] [PDF] |
||||
![]() |
O. Mathieu and J. Bender RNA-directed DNA methylation J. Cell Sci., October 1, 2004; 117(21): 4881 - 4888. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Melquist and J. Bender An Internal Rearrangement in an Arabidopsis Inverted Repeat Locus Impairs DNA Methylation Triggered by the Locus Genetics, January 1, 2004; 166(1): 437 - 448. [Abstract] [Full Text] [PDF] |
||||