title: Overgrowth caused by misexpression of a microRNA with dispensable wild-type function.
abstract: MicroRNAs (miRNAs) represent an abundant class of non-coding RNAs that negatively regulate gene expression, primarily at the post-transcriptional level. miRNA genes are frequently located in proximity to fragile chromosomal sites associated with cancers and amplification of a miRNA cluster has been correlated with the etiology of lymphomas and solid tumors. The oncogenic potential of a miRNA polycistron has recently been demonstrated in vivo. Here, we show that misexpression of the Drosophila miRNA mirvana/mir-278 in the developing eye causes massive overgrowth, in part due to inhibition of apoptosis. A single base substitution affecting the mature miRNA blocks the gain-of-function phenotype but is not associated with a detectable reduction-of-function phenotype when homozygous. This result demonstrates that misexpressed miRNAs may acquire novel functions that cause unscheduled proliferation in vivo and thus exemplifies the potential of miRNAs to promote tumor formation.
authors.affiliation: Zoologisches Institut der Universität Zürich, Winterthurer Strasse 190, 8057 Zürich, Switzerland. knud.nairz@usz.ch
authors.forename: Knud
authors.initials: K
authors.lastname: Nairz
authors.forename: Carmen
authors.initials: C
authors.lastname: Rottig
authors.forename: Felix
authors.initials: F
authors.lastname: Rintelen
authors.forename: Evgeny
authors.initials: E
authors.lastname: Zdobnov
authors.forename: Martin
authors.initials: M
authors.lastname: Moser
authors.forename: Ernst
authors.initials: E
authors.lastname: Hafen
mesh_terms: D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D049109:Cell Proliferation; D004330:Drosophila / Q000196:embryology / Q000254:growth & development*; D005123:Eye / Q000196:embryology*; D005260:Female; D008297:Male; D035683:MicroRNAs / Q000502:physiology*; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000209:etiology
chemical_list: D035683:MicroRNAs