title: Post-transcriptional regulation of microRNA expression.
abstract: microRNAs (miRNAs) are endogenous, noncoding approximately 22-nucleotide RNA molecules that have recently emerged as fundamental, post-transcriptional regulators of cognate target gene expression. Many mammalian miRNAs are expressed in a tissue-specific manner, a phenomenon that has so far been attributed to transcriptional regulation. We here show by Northern blots and in situ hybridization experiments that the expression of mammalian miRNAs can be regulated at the post-transcriptional level. In particular, miR-138 is spatially restricted to distinct cell types, while its precursor, pre-miR-138-2, is ubiquitously expressed throughout all tissues analyzed. Furthermore, pre-miR-138-2 is exported from the nucleus to the cytoplasm, suggesting that cleavage of this pre-miRNA by Dicer is restricted to certain tissues and cell types. Thus, differential processing of pre-miRNAs might be an alternative mechanism to control miRNA function.
authors.affiliation: Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria.
authors.forename: Gregor
authors.initials: G
authors.lastname: Obernosterer
authors.forename: Philipp J F
authors.initials: PJ
authors.lastname: Leuschner
authors.forename: Mattias
authors.initials: M
authors.lastname: Alenius
authors.forename: Javier
authors.initials: J
authors.lastname: Martinez
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D012322:RNA Precursors / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D015183:Restriction Mapping
chemical_list: D035683:MicroRNAs; D012322:RNA Precursors