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RNA polymerase IVa is a multisubunit RNA polymerase complex found in the nucleus of plants and involved in accumulation of siRNAs and in DNA methylation-dependent silencing of endogenous repeated sequences. Two large subunits comprise the most conserved portion including the catalytic site and share similarity with other eukaryotic and bacterial multisubunit RNA polymerases. The second largest subunit is also found in RNA polymerase IVb, while the largest subunit is found only in the IVa complex. The remainder of the complex is composed of smaller subunits. Any constituent part of the nucleus, a membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated. A protein complex, located in the nucleus, that possesses DNA-directed RNA polymerase activity. That part of the nuclear content other than the chromosomes or the nucleolus. Any constituent part of the nucleoplasm, that part of the nuclear content other than the chromosomes or the nucleolus. RNA polymerase IV is a multisubunit RNA polymerase complex found in the nucleus of plants. In addition to RNA polymerases I, II, and III, the essential RNA polymerases present in all eukaryotes, plants have two additional nuclear RNA polymerases, Pol IV and Pol V, that play nonredundant roles in siRNA-directed DNA methylation and gene silencing. Pol IV is required for siRNA production and Pol V is required for generating noncoding transcripts at target loci. Pol IV is composed of subunits that are paralogous or identical to the 12 subunits of Pol II. The largest and second-largest subunits of Pol IV are the catalytic subunits and share similarity with the corresponding subunits of other eukaryotic and bacterial multisubunit RNA polymerases. RNA polymerase IVb is a multisubunit RNA polymerase complex found in the nucleus of plants and involved in accumulation of siRNAs and in DNA methylation-dependent silencing of endogenous repeated sequences. Two large subunits comprise the most conserved portion including the catalytic site and share similarity with other eukaryotic and bacterial multisubunit RNA polymerases. The second largest subunit is also found in RNA polymerase IVa, while the largest subunit is found only in the IVa complex and contains an extended C-terminal domain (CTD) that includes multiple repeats of a 16 amino-acid consensus sequence as well as other sequences. The remainder of the complex is composed of smaller subunits. A protein complex that possesses DNA-directed RNA polymerase activity.

View Gene Ontology (GO) Term

GO TERM SUMMARY
Name: DNA-directed RNA polymerase IV complex
Acc: GO:0000418
Aspect: Cellular Component
Desc: RNA polymerase IV is a multisubunit RNA polymerase complex found in the nucleus of plants. In addition to RNA polymerases I, II, and III, the essential RNA polymerases present in all eukaryotes, plants have two additional nuclear RNA polymerases, Pol IV and Pol V, that play nonredundant roles in siRNA-directed DNA methylation and gene silencing. Pol IV is required for siRNA production and Pol V is required for generating noncoding transcripts at target loci. Pol IV is composed of subunits that are paralogous or identical to the 12 subunits of Pol II. The largest and second-largest subunits of Pol IV are the catalytic subunits and share similarity with the corresponding subunits of other eukaryotic and bacterial multisubunit RNA polymerases.
Proteins in PDR annotated with:
   This term: 12 [Search]
   Term or descendants: 12 [Search]


[geneontology.org]
INTERACTIVE GO GRAPH

GO:0000418 - DNA-directed RNA polymerase IV complex (interactive image map)
YRC Informatics Platform - Version 3.0
Created and Maintained by: Michael Riffle