Intron-mediated enhancement (IME) is the ability of an intron sequence to enhance the expression of a gene containing that intron. The term was first defined in a 1990 publication that investigated the enhancing effects of two specific maize introns. Since then there have been a number of publications that have investigated this phenomenon, though the mechanism(s) by which IME works are still not completely understood. When testing to see whether any given intron produces an IME effect, it is typical to compare the expression of two constructs, one containing the intron and one without it, and to express the difference between the two results as a "fold increase" in enhancement.
Not all introns enhance gene expression, but those that do typically enhance expression between 2– and 10–fold relative to an intronless control. Introns that enhance expression have been detected in humans, mice, Arabidopsis, rice, and C. elegans.
- Mascarenhas, D; Mettler, IJ; Pierce, DA; Lowe, HW (1990). "Intron-mediated enhancement of heterologous gene expression in maize". Plant Molecular Biology 15 (6): 913–920. doi:10.1007/BF00039430. PMID 2103480. "no"
- Rose, A (2002). "Requirements for intron-mediated enhancement of gene expression in Arabidopsis". RNA 8 (11): 1444–53. doi:10.1017/S1355838202020551. PMC 1370350. PMID 12458797.
- Jonsson, JJ; Foresman, MD; Wilson, N; McIvor, RS (1990). "Intron requirement for expression of the human purine nucleoside phosphorylase gene". Nucleic Acids Research 20 (12): 3191–3198. doi:10.1093/nar/20.12.3191. PMC 312458. PMID 1620616.
- Palmiter, RD; Sandgren, EP; Avarbock, MR; Allen, DD; Brinster, RL (1991). "Heterologous introns can enhance expression of transgenes in mice". PNAS 88 (2): 478–482. doi:10.1073/pnas.88.2.478. PMC 50834. PMID 1988947. "no"
- Rose, AB; Last, RL (2003). "Introns act post-transcriptionally to increase expression of the Arabidopsis thaliana tryptophan pathway gene PAT1". The Plant Journal 11 (3): 455–464. doi:10.1046/j.1365-313X.1997.11030455.x. PMID 9107035.
- Jeon, JS; Lee, S; Jung, KH; Jun, SH; Kim, C; An, G (2000). "Tissue-Preferential Expression of a Rice α-Tubulin Gene, OsTubA1, Mediated by the First Intron". Plant Physiology 123 (3): 1005–1014. doi:10.1104/pp.123.3.1005. PMC 59063. PMID 10889249.
- Morello, L; Bardini, M; Sala, F; Breviario, D (2002). "A long leader intron of the Ostub16 rice β-tubulin gene is required for high-level gene expression and can autonomously promote transcription both in vivo and in vitro". The Plant Journal 29 (1): 33–44. doi:10.1046/j.0960-7412.2001.01192.x. PMID 12060225.
- Ho, SH; So, GMK; Chow, KL (2001). "Postembryonic expression of Caenorhabditis elegans mab-21 and its requirement in sensory ray differentiation". Developmental Dynamics 221 (4): 422–430. doi:10.1002/dvdy.1161. PMID 11500979.