Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2005 Dec;11(12):1753-61.
doi: 10.1261/rna.2248605.

MicroRNA function: multiple mechanisms for a tiny RNA?

Ramesh S Pillai  1
Affiliations
Review

MicroRNA function: multiple mechanisms for a tiny RNA?

Ramesh S Pillai. RNA. 2005 Dec.

Abstract

MicroRNAs are sequence-specific regulators of post-transcriptional gene expression in many eukaryotes. They are believed to control the expression of thousands of target mRNAs, with each mRNA believed to be targeted by multiple microRNAs. Recent studies have uncovered various mechanisms by which microRNAs down-regulate their target mRNAs and have linked a well-known subcellular structure, the cytoplasmic processing bodies (PBs) to the microRNA pathway. The finding that microRNAs are misexpressed in cancers has reinforced the idea that their regulatory roles are very important.

PubMed Disclaimer

Figures

FIGURE 1.
FIGURE 1.
Models of miRNA function. The two-step model: Upon binding to the 3′-UTR of a target mRNA, the miRNP complex inhibits translation initiation, presumably by interfering with the 7mG cap function in recruiting eIF4E. Next, the repressed mRNA:miRNP complex is moved to the P-bodies (PBs) for storage. It is speculated that there are separate compartments for storage of the repressed mRNA and for the core PB components such as Dcp1, Xrn1, etc. It is possible that a part of the stored mRNA is degraded via decapping or that once repression is released, they exit the PBs and re-enter translation. One-step model: Binding of the miRNP to the target mRNA directs the mRNA to the PBs. Disassembly of ribosomes on the message occurs prior to entry into the PBs. The mRNA can then be either degraded or stored for later reuse. 7mG, 7-methyl guanine; AAAA, polyadenosine tail; 4E, eIF4E; 4G, eIF4G.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Ambros, V. 2003. MicroRNA pathways in flies and worms: Growth, death, fat, stress, and timing. Cell 113: 673–676. - PubMed
    1. Andrei, M.A., Ingelfinger, D., Heintzmann, R., Achsel, T., Rivera-Pomar, R., and Luhrmann, R. 2005. A role for eIF4E and eIF4E-transporter in targeting mRNPs to mammalian processing bodies. RNA 11: 717–727. - PMC - PubMed
    1. Bagga, S., Bracht, J., Hunter, S., Massirer, K., Holtz, J., Eachus, R., and Pasquinelli, A.E. 2005. Regulation by let-7 and lin-4 miRNAs results in target mRNA degradation. Cell 122: 553–563. - PubMed
    1. Bartel, D.P. 2004. MicroRNAs: Genomics, biogenesis, mechanism, and function. Cell 116: 281–297. - PubMed
    1. Bartel, D.P. and Chen, C.Z. 2004. Micromanagers of gene expression: The potentially widespread influence of metazoan microRNAs. Nat. Rev. Genet. 5: 396–400. - PubMed

Publication types

LinkOut - more resources