Open AccessStructure and RNA template requirements of Arabidopsis RNA-DEPENDENT RNA POLYMERASE 2
Author(s) -
Akihito Fukudome,
Jasleen Singh,
Vibhor Mishra,
Bharat Madan,
Francisco Martínez-Márquez,
Sabine Wenzel,
Rui Yan,
Momoko Shiozaki,
Zhiheng Yu,
Joseph Che Yen Wang,
Yuichiro Takagi,
Craig S. Pikaard
Publication year - 2021
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2115899118
Subject(s) - rna , transcription (linguistics) , processivity , rna polymerase iii , rna dependent rna polymerase , base pair , biology , dna , microbiology and biotechnology , rna polymerase ii , transcription bubble , rna polymerase , polymerase , rna polymerase i , genetics , promoter , gene , gene expression , linguistics , philosophy
Significance RDR2 is critical for siRNA-directed DNA methylation inArabidopsis , functioning in physical association with DNA-dependent Pol IV to synthesize the second strands of double-stranded siRNA precursors. Base-pairing between the DNA template strand transcribed by Pol IV and the nontemplate DNA strand is needed to induce Pol IV arrest and Pol IV/RDR2 transcriptional coupling, but how this occurs is unknown. We report the structure of RDR2 and experimental evidence for how RDR2 engages its RNA templates and initiates transcription. RDR2 engages the ends of RNAs displaced from RNA/DNA hybrids, suggesting a model in which Pol IV arrest and backtracking, accompanied by DNA strand reannealing, extrudes the 3′ end of the Pol IV transcript, allowing RNA engagement and second-strand synthesis by RDR2.