Structural Variant of a Tandem Repeat-containing Silencer Locus Reveals Distinct Pol II and Pol IV-dependent Pathways of siRNA Biogenesis. Arabidopsis thaliana

We used a two-component transgene system to study the RNA-dependent DNA methylation (RdDM) and transcriptional gene silencing (TGS) in Arabidopsis. By profiling the small RNA population in mutants defected in RdDM or RNA polymerase II-transcribed trigger for generating silencing siRNA, we investigated how repetitive loci such as tandem repeats were regulated transcriptionally through the action of RNA polymerase IV. Overall design: Genome-wide small RNA profiling was done by Illumina TruSeq sample preparation followed by high-throughput sequencing with the Illumina HiSeq 2000 platform. The six samples represent mutants and their corresponding control lines.