Dynamic localisation of mature microRNAs in Human nucleoli is influenced by exogenous genetic materials.
Although microRNAs are commonly known to function as a component of RNA-induced silencing complexes in the cytoplasm, they have been detected in other organelles, notably the nucleus and the nucleolus, of mammalian cells. We have conducted a systematic search for miRNAs in HeLa cell nucleoli, and identified 11 abundant miRNAs with a high level of nucleolar accumulation. Through in situ hybridisation, we have localised these miRNAs, including miR-191 and miR-484, in the nucleolus of a diversity of human and rodent cell lines. The nucleolar association of these miRNAs is resistant to various cellular stresses, but highly sensitive to the presence of exogenous nucleic acids. Introduction of both single- and double-stranded DNA as well as double stranded RNA rapidly induce the redistribution of nucleolar miRNAs to the cytoplasm. A similar change in subcellular distribution is also observed in cells infected with the influenza A virus. The partition of miRNAs between the nucleolus and the cytoplasm is affected by Leptomycin B, suggesting a role of Exportin-1 in the intracellular shuttling of miRNAs. This study reveals a previously unknown aspect of miRNA biology, and suggests a possible link between these small noncoding RNAs and the cellular management of foreign genetic materials.
Departments of Biology and Chemistry, City University of Hong Kong, Hong Kong, China.
Zhou Fang
ZF
Li
Yi Min
YM
Liang
Pui Ngan
PN
Lau
Wei
W
Shen
Dai Kui
DK
Wang
Wing Tai
WT
Cheung
Chun Jason
CJ
Xue
Lit Man
LM
Poon
Yun Wah
YW
Lam
D000818:Animals; D001692:Biological Transport / Q000235:genetics; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003593:Cytoplasm / Q000235:genetics / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000502:physiology; D007251:Influenza, Human / Q000235:genetics; D020071:Interspersed Repetitive Sequences / Q000502:physiology*; D061986:MCF-7 Cells; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D014780:Viruses / Q000235:genetics*
D035683:MicroRNAs