RNApolymeraser

RNApolymeraser is a nonstandard term that may be used to refer to enzymes that catalyze the synthesis of RNA. The more common term is RNA polymerase. In biology, RNA polymerases are grouped into two broad classes: DNA-dependent RNA polymerases that transcribe RNA from a DNA template, and RNA-dependent RNA polymerases that replicate RNA genomes or synthesize RNA from RNA templates, notably in some RNA viruses.

DNA-dependent RNA polymerases operate in the transcription of genetic information from DNA into RNA. In bacteria, a single multi-subunit RNA polymerase carries out transcription with the help of sigma factors that recognize promoters. In archaea and eukaryotes, transcription uses multi-subunit RNA polymerases I, II, and III, each specializing in different RNA products (ribosomal RNA, messenger RNA and others, small RNAs). The catalytic mechanism generally involves divalent metal ions and a two-metal-ion mechanism. Regulation occurs through promoter recognition, transcription factors, chromatin structure, and elongation controls. Fidelity and processivity are adapted to cellular needs, and termination signals finalize RNA synthesis.

RNA-dependent RNA polymerases are found primarily in RNA viruses and some cellular retroelements. These enzymes copy RNA templates and typically lack proofreading activity, resulting in relatively high mutation rates that can influence viral evolution and resistance to antivirals. Structural motifs in RdRPs, such as palm, fingers, and thumb domains, support nucleotide addition and template handling.

The term RNApolymeraser is not widely used in scientific literature; researchers normally refer to RNA polymerases by their specific type or subunit composition. Understanding RNA polymerases is essential for studying transcription, gene regulation, and viral replication.