The covalent transfer of a methyl group, to C-5 or N-4, of a cytosine located within an asymmetric CHH sequence in a DNA molecule. H stands for an adenine, cytosine, or thymine nucleotide.

The process in which double-stranded RNAs silence cognate genes. Involves posttranscriptional gene inactivation ('silencing') both of transgenes or dsRNA introduced into a germline, and of the host gene(s) homologous to the transgenes or dsRNA. This silencing is triggered by the introduction of transgenes or double-stranded RNA (dsRNA), and can occur through a specific decrease in the level of mRNA, or by negative regulation of translation, of both host genes and transgenes.

RNA polymerase IV 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. 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. The second largest subunit is also found in RNA polymerase V, while the largest subunit is found only in RNAP IV complex.

RNA polymerase IV 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. 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. The second largest subunit is also found in RNA polymerase V, while the largest subunit is found only in RNAP IV complex.

RNA polymerase V 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. Pol V is composed of subunits that are paralogous or identical to the 12 subunits of Pol II. 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.

RNA polymerase V 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. Pol V is composed of subunits that are paralogous or identical to the 12 subunits of Pol II. 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 membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated. In most cells, the nucleus contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing. In some species, or in specialized cell types, RNA metabolism or DNA replication may be absent.