Welcome to the polymerase database!
In eukaryotes, three functionally divergent RNA polymerase complexes (Pol I, Pol II and Pol III) are required for ribosomal RNA, messenger RNA and transfer RNA synthesis, respectively, amongst other essential RNA products. In plants, RNA polymerases IV and V (Pol IV and Pol V) evolved from Pol II and are critical for transposable element silencing. Obtaining comprehensive information about all these complexes across diverse organisms is time-consuming and error-prone due to the generic functional annotations typically assigned to RNA polymerase subunits in genomic databases. To address this challenge, we present an expert-curated database including experimental and phylogenetic knowledge on RNA polymerase complexes and their constituent proteins using a relational data model and user-friendly interface. Our aim is to facilitate the study of diverse RNA polymerases, to better understand their evolution, and to accelerate the gathering of structure-function insight in this field. Our website features curated information on all the nuclear RNA polymerases of plants (Pol I, II, III, IV and V). Users can explore tabular records for each enzyme’s experimentally determined or predicted composition, obtain graphical representations of the distinct complexes, download protein FASTA files, and filter these datasets by species or subunits of interest. We have compiled a wide-ranging collection of RNA polymerase-associated proteins from diverse species, including hitherto missing, truncated or misannotated subunits. This resource will allow researchers interested in transcription, noncoding RNAs and epigenetics to conduct precise studies of RNA polymerase regulation, post-translational modification, localization and turnover, as well as facilitating phylogenetic analyses. With this database, we aim to foster collaboration and promote reproducible studies of these essential cellular machineries.
Pol IV evolution
Plants express RNA Pol IV and Pol V in addition to the universally conserved eukaryotic Pol I, Pol II and Pol III.
Subunit compositions of Pol II, Pol IV and Pol V in Arabidopsis thaliana
As NRPD1 (Pol IV) shares a common progenitor with NRPB1 (Pol II) and NRPE1 (Pol V), these proteins are homologous throughout most of their lengths and show similarity in lany core RNA polymerase domains.
Polymerase IV recruitment factors
Pol IV is recruited to TE regions in chromatin via docking to distinct CLSY family SNF2 proteins.
