NEW YORK, May 17 (GenomeWeb News) - Following is a description of two recently published research papers recommended by a scientist involved in integrated biology. The recommender, Shiv Grewal, is a senior investigator at the NCI's Center for Cancer Research.
For a complete list of recommended papers, read Genome Technology, a GenomeWeb News sister publication.
RNA Polymerase IV Directs Silencing of Endogenous DNA Herr AJ, JensenMB, Dalmay T, BaulcombeDCScience. 2005 Feb 24.
Plant Nuclear RNA Polymerase IV Mediates siRNA and DNA Methylation-Dependent Heterochromatin Formation
Onodera Y, Haag J, Ream T, Costa Nunes P, Pontes O, Pikaard C. Cell. 2005 March 11; 120, 613-622.
These two papers address a plant-specific RNA polymerase known as Pol IV (all eukaryotes have three nuclear DNA-dependent RNA polymerases, namely, Pol I, II, and III). In the Science paper, researchers at the Sainsbury Laboratory of the John Innes Centre in Norwich, UK, show how Pol IV silences certain transposons and repetitive DNA in a short interfering RNA pathway involving RNA-dependent RNA polymerase 2 and Dicer-Like 3. The authors conclude that the existence of this distinct silencing polymerase may explain the involvement of an RNA silencing pathway in the maintenance of transcriptional silencing.
In the Cell paper, corresponding author Craig Pikaard, a biologist at WashingtonUniversityin St. Louis, writes that the data in the paper suggest that Pol IV helps produce siRNAs that target de novo cytosine methylation events required for facultative heterochromatin formation and higher-order heterochromatin associations.
Shiv Grewalat NCI adds that the results presented in these papers are important for RNAi researchers because they suggest that low-level transcription of transposable elements by RNA polymerase might be essential for generating small interfering RNAs, which then help target heterochromatin complexes.