Nucleic Acids Research Advance Access originally published online on October 25, 2007
Nucleic Acids Research 2007 35(21):7336-7347; doi:10.1093/nar/gkm863
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Nucleic Acids Research, 2007, Vol. 35, No. 21 7336-7347
© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-com
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Expression of a novel non-coding mitochondrial RNA in human proliferating cells
1Bios Chile Ingeniería Genética S.A., 2Institute for Fundamental and Applied Biology, Fundación Ciencia para la Vida, Avenida Zañartu 1482, 3Laboratorio de Biología Celular y Molecular and Department of Urology, Facultad de Ciencias de la Salud, Universidad Andrés Bello, República 252, Santiago, Chile and 4Ludwig Institute for Cancer Research, Sao Paulo, Brazil
* To whom correspondence should be addressed. Tel: +56 2 473 6133; Fax: +56 2 2394250; Email: lburzio{at}bioschile.cl
Received August 20, 2007. Revised September 21, 2007. Accepted September 26, 2007.
Previously, we reported the presence in mouse cells of a mitochondrial RNA which contains an inverted repeat (IR) of 121 nucleotides (nt) covalently linked to the 5' end of the mitochondrial 16S RNA (16S mtrRNA). Here, we report the structure of an equivalent transcript of 2374 nt which is over-expressed in human proliferating cells but not in resting cells. The transcript contains a hairpin structure comprising an IR of 815 nt linked to the 5' end of the 16S mtrRNA and forming a long double-stranded structure or stem and a loop of 40 nt. The stem is resistant to RNase A and can be detected and isolated after digestion with the enzyme. This novel transcript is a non-coding RNA (ncRNA) and several evidences suggest that the transcript is synthesized in mitochondria. The expression of this transcript can be induced in resting lymphocytes stimulated with phytohaemagglutinin (PHA). Moreover, aphidicolin treatment of DU145 cells reversibly blocks proliferation and expression of the transcript. If the drug is removed, the cells re-assume proliferation and over-express the ncmtRNA. These results suggest that the expression of the ncmtRNA correlates with the replicative state of the cell and it may play a role in cell proliferation.
The authors wish it to be known that, in their opinion, the first three authors should be regarded as joint First Authors