Small RNAs break out: the molecular cell biology of mobile small RNAs

• Published in: Nature reviews. Molecular cell biology Vol. 15; no. 8; pp. 525 - 535
• Main Authors: Sarkies, Peter, Miska, Eric A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2014; Nature Publishing Group
• Subjects: 631/136/334/1582/712; 631/337/384; 631/337/384/2053; 631/337/505; Animals; Biochemistry; Biological Transport; Biology; Biosynthesis; Caenorhabditis elegans - genetics; Caenorhabditis elegans - metabolism; Cancer Research; Cell Biology; Cell interaction; Developmental Biology; DNA methylation; Enzymes; Epigenesis, Genetic; Epigenetics; Flowers & plants; Genetic aspects; Humans; Immunity - genetics; Life Sciences; MicroRNAs; Mobility; Nematoda; Nematodes; Plants - genetics; Plants - metabolism; Properties; review-article; RNA; RNA, Small Interfering; RNA, Small Untranslated - genetics; RNA, Small Untranslated - metabolism; Signal Transduction - genetics; Stem Cells; Virus Diseases - genetics; Virus Diseases - immunology
• ISSN: 1471-0072; 1471-0080
• DOI: 10.1038/nrm3840

Key Points Small RNAs can move between cells and function at transcriptional and post-transcriptional levels to transmit gene regulatory information. In plants, both 24-nucleotide-long (24-nt-long) and 21-nt-long siRNA duplexes are able to move from cell to cell over short ranges and over long distances through the phloem. However, whether the small RNAs can transmit information may depend on the recipient cell. In Caenorhabditis elegans , specific channel proteins are required for small RNA mobility, but their mechanisms are still unclear. Mobile RNAs can be inherited from one generation to the next and can move from one organism to another, even crossing species barriers. There is evidence that small RNAs are secreted from mammalian cells, but their functional importance is still unclear. Mobile RNAs function in antiviral defence, cell signalling and gene expression regulation, and might also mediate transgenerational epigenetic inheritance. Genetic and molecular studies in plants and nematodes have begun to provide insights into the mechanisms underlying RNA movement, its functions and the nature of mobile RNA molecules. Small RNAs that function in a non-cell autonomous manner are becoming increasingly recognized as regulatory molecules with the potential to transmit information between cells, organisms and species. In plants and nematodes, small RNA mobility can be genetically dissected to provide information about the nature of the mobile RNA species, their distribution in the organism and inside cells, as well as the cellular machinery required for mobility, including channel proteins and cellular trafficking factors. Mobile RNAs function in antiviral defence, cell signalling and gene expression regulation, and might also mediate transgenerational epigenetic inheritance.