widespread regulation of mirna biogenesis at the dicer step by the cold-inducible rna-binding protein, rbm3microrna的生物起源的广泛监管帽子一步cold-inducible rna结合蛋白,rbm3.pdf

Widespread Regulation of miRNA Biogenesis at the Dicer Step by the Cold-Inducible RNA-Binding Protein, RBM3 1 2 1 Julie Pilotte , Esther E. Dupont-Versteegden , Peter W. Vanderklish * 1 Department of Neurobiology, The Scripps Research Institute, La Jolla, California, United States of America, 2 Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky, United States of America Abstract MicroRNAs (miRNAs) play critical roles in diverse cellular events through their effects on translation. Emerging data suggest that modulation of miRNA biogenesis at post-transcriptional steps by RNA-binding proteins is a key point of regulatory control over the expression of some miRNAs and the cellular processes they influence. However, the extent and conditions under which the miRNA pathway is amenable to regulation at posttranscriptional steps are poorly understood. Here we show that RBM3, a cold-inducible, developmentally regulated RNA-binding protein and putative protooncogene, is an essential regulator of miRNA biogenesis. Utilizing miRNA array, Northern blot, and PCR methods, we observed that over 60% of miRNAs detectable in a neuronal cell line were significantly downregulated by knockdown of RBM3. Conversely, for select miRNAs assayed by Northern blot, induction of RBM3 by overexpression or mild hypothermia increased their levels. Changes in miRNA expression were accompanied by changes in the levels of their ,70 nt precursors, whereas primary transcript levels were unaffected. Mechanistic studies revealed that knockdown of RBM3 does not reduce Dicer activity or impede transport of pre-miRNAs into the cytoplasm. Rather, we find that RBM3 binds directly to ,70 nt pre-miR