RNA Polymerase IV Functions in Paramutation in Zea mays

Science ◽  
2009 ◽  
Vol 323 (5918) ◽  
pp. 1201-1205 ◽  
Author(s):  
K. F. Erhard ◽  
J. L. Stonaker ◽  
S. E. Parkinson ◽  
J. P. Lim ◽  
C. J. Hale ◽  
...  
Keyword(s):  
Zea Mays ◽  
Rna Polymerase ◽  
Rna Polymerase Iv

scholarly journals Locus-specific paramutation in Zea mays is maintained by a PICKLE-like chromodomain helicase DNA-binding 3 protein controlling development and male gametophyte function

PLoS Genetics ◽  
2020 ◽  
Vol 16 (12) ◽  
pp. e1009243
Author(s):  
Natalie C. Deans ◽  
Brian J. Giacopelli ◽  
Jay B. Hollick
Keyword(s):  
Zea Mays ◽  
Gene Regulation ◽  
Dna Binding ◽  
Rna Polymerase ◽  
Male Gametophyte ◽  
Mendelian Inheritance ◽  
Developmental Defects ◽  
Rna Biogenesis ◽  
Rna Polymerase Iv ◽  
Mutant Phenotypes

Paramutations represent directed and meiotically-heritable changes in gene regulation leading to apparent violations of Mendelian inheritance. Although the mechanism and evolutionary importance of paramutation behaviors remain largely unknown, genetic screens in maize (Zea mays) identify five components affecting 24 nucleotide RNA biogenesis as required to maintain repression of a paramutant purple plant1 (pl1) allele. Currently, the RNA polymerase IV largest subunit represents the only component also specifying proper development. Here we identify a chromodomain helicase DNA-binding 3 (CHD3) protein orthologous to Arabidopsis (Arabidopsis thaliana) PICKLE as another component maintaining both pl1 paramutation and normal somatic development but without affecting overall small RNA biogenesis. In addition, genetic tests show this protein contributes to proper male gametophyte function. The similar mutant phenotypes documented in Arabidopsis and maize implicate some evolutionarily-conserved gene regulation while developmental defects associated with the two paramutation mutants are largely distinct. Our results show that a CHD3 protein responsible for normal plant ontogeny and sperm transmission also helps maintain meiotically-heritable epigenetic regulatory variation for specific alleles. This finding implicates an intersection of RNA polymerase IV function and nucleosome positioning in the paramutation process.

scholarly journals Identification of Pol IV and RDR2-dependent precursors of 24 nt siRNAs guiding de novo DNA methylation in Arabidopsis

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Todd Blevins ◽  
Ram Podicheti ◽  
Vibhor Mishra ◽  
Michelle Marasco ◽  
Jing Wang ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Cytosine Methylation ◽  
De Novo ◽  
Transferase Activity ◽  
Small Interfering Rnas ◽  
Pol Iv ◽  
Nuclear Rna ◽  
Rna Polymerase Iv ◽  
Nuclear Rna Polymerase

In Arabidopsis thaliana, abundant 24 nucleotide small interfering RNAs (24 nt siRNA) guide the cytosine methylation and silencing of transposons and a subset of genes. 24 nt siRNA biogenesis requires nuclear RNA polymerase IV (Pol IV), RNA-dependent RNA polymerase 2 (RDR2) and DICER-like 3 (DCL3). However, siRNA precursors are mostly undefined. We identified Pol IV and RDR2-dependent RNAs (P4R2 RNAs) that accumulate in dcl3 mutants and are diced into 24 nt RNAs by DCL3 in vitro. P4R2 RNAs are mostly 26-45 nt and initiate with a purine adjacent to a pyrimidine, characteristics shared by Pol IV transcripts generated in vitro. RDR2 terminal transferase activity, also demonstrated in vitro, may account for occasional non-templated nucleotides at P4R2 RNA 3’ termini. The 24 nt siRNAs primarily correspond to the 5’ or 3’ ends of P4R2 RNAs, suggesting a model whereby siRNAs are generated from either end of P4R2 duplexes by single dicing events.

Action of Trifluralin on Chromatin Activity in Corn and Soybean

Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 364-366 ◽  
Author(s):  
Donald Penner ◽  
Roy W. Early
Keyword(s):  
Escherichia Coli ◽  
Zea Mays ◽  
Glycine Max ◽  
Rna Polymerase ◽  
Melting Temperature ◽  
Ribonucleic Acid ◽  
Rna Synthesis ◽  
Subsequent Reduction

Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) at 10−5M applied to etiolated corn(Zea maysL. ‘Michigan 500′) seedlings 6 or 12 hr before the isolation of chromatin from the roots markedly reduced ribonucleic acid (RNA) synthesis supported by the chromatin. The addition ofEscherichia coliRNA polymerase failed to overcome the inhibition. Trifluralin increased the melting temperature of the chromatin. The presence of trifluralin during the isolation and reaction procedure inhibited RNA synthesis indicating possible trifluralin binding to the chromatin with subsequent reduction of template availability for transcription. Trifluralin did not inhibit chromatin activity in soybean [Glycine max(L.) Merr. ‘Hark’] seedlings.

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