Intron

Article By:

Müller, Werner E. G. Institut für Physiologische Chemie, Universität Mainz, Mainz, Germany.

Rae, Peter M. M. Molecular Diagnostics, Inc., West Haven, Connecticut.

Last reviewed:January 2020

DOI:https://doi.org/10.1036/1097-8542.350450

A segment of deoxyribonucleic acid (DNA) transcribed into ribonucleic acid (RNA) as part of a longer strand of RNA, called heterogeneous nuclear RNA (hnRNA), but which does not survive the processes of messenger RNA (mRNA) maturation. Genes are split into portions, termed exons, which appear in mRNAs or in structural RNAs, and introns. During the maturation of pre-mRNA to mature mRNA, a series of control processes occur that specify and narrow down the set of mRNAs that become functionally active in a given cell. These processes multiply the species of transcripts through the differential combination of exons and the inclusion of parts of introns into the functional mRNAs; thus, several mRNA products can be generated from a single gene in a controlled manner. For example, certain exons may be included or spliced out during mRNA maturation (alternative splicing of the same hnRNA molecule), or two different hnRNA molecules may form during the splicing reaction of one mRNA transcript, which is a process termed trans-splicing. See also: Deoxyribonucleic acid (DNA); Exon; Gene; Genetic mapping; Ribonucleic acid (RNA)

The content above is only an excerpt.