ribonucleic acid abbr., RNA (rus. рибонуклеиновая кислота abbr., РНК) — Linear polymer formed by covalently bound ribonucleotide monomers.


Ribonucleic acids (RNA) are nucleotide polymers which contain phosphoric acid residue, ribose (as opposed to DNA which contains deoxyribose) and nitrogen bases: adenine, cytosine, guanine, and uracil (as opposed to DNA which contains thymine instead of uracil). RNA is present in the cells of all living organisms and in some viruses. In RNA-containing viruses RNA serves as a carrier of genetic information. Most RNA molecules are single-stranded, though rare examples of double-stranded RNA molecules are known. There are 3 basic types of RNA: ribosomal (rRNA), transport (tRNA) and messenger or matrix (mRNA). Messenger RNA is used to transfer information encoded in DNA to ribosomes for protein synthesis. The coding sequence of mRNA determines the amino acid sequence of a protein chain. However, the vast majority of RNAs do not encode proteins (e.g., tRNA and rRNA). There are some other non-coding RNAs such as the RNA involved in gene regulation and mRNA processing, and the RNA catalysing the cleavage and ligation of RNA molecules. By analogy with proteins capable of catalysing chemical reactions (enzymes), catalytic RNA molecules are called ribozymes. Micro-RNAs (20-22 base pairs) and small interfering RNAs (siRNA, 20-25 base pairs) can reduce or increase gene expression through the RNA interference. Specific RNA interference pathway proteins are guided by micro- and siRNAs to the targeted mRNA sequences and cleave them thus interfering with translation. Promising new technology for cancer gene therapy based on the RNA interference mechanism aimed to "silence" genes responsible for promoting the growth of cancer cells is being developed. Currently, targeted delivery of siRNAs to tumour cells by nanoparticles is under active development.


  • Naroditsky Boris S.
  • Shirinsky Vladimir P.
  • Nesterenko Lyudmila N.


  1. Alberts B., Johnson A., Lewis J. et al. Molecular Biology of the Cell. 4th ed. — N.Y.: Garland Publishing, 2002. — 265 p.
  2. E. Ris et al. Basics of Molecular Biology. From cells to atoms. — Moscow.: Mir, 2002. — 154 P. RNA // Wikipedia, the free encyclopedia. — http://en.wikipedia.org/wiki/RNA (reference date: 12.12.2011).

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