Post-transcriptional regulation of microRNA expression

• DOI: 10.1261/rna.2322506
• Publication Date: 2006-06-01T00:49:00Z
• Authors: Gregor Obernosterer; Philipp J.F. Leus...; Mattias Alenius; Javier Martinez
• Keywords: 0301 basic medicine; Base Sequence; Molecular Sequence Data; Restriction Mapping; Cell Line; Mice; MicroRNAs; 03 medical and health sciences; Gene Expression Regulation; RNA Precursors; Animals; Humans; RNA Processing, Post-Transcriptional; HeLa Cells

microRNAs (miRNAs) are endogenous, noncoding ∼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.