title: Common logic of transcription factor and microRNA action.
abstract: Over the past few years, microRNAs (miRNAs) have emerged as abundant regulators of gene expression. Like many transcription factors (TFs), miRNAs are important determinants of cellular fate specification. Here I provide a conceptual framework for miRNA action in the context of creating cellular diversity in a developing organism, and emphasize the conceptual similarity of TF- and miRNA-mediated control of gene expression. Both TFs and miRNAs are trans-acting factors that exert their activity through composite cis-regulatory elements that are 'hard-wired' into DNA or RNA. TFs and miRNAs act in a largely combinatorial manner - that is, many different TFs or miRNAs control one gene - and they act cooperatively on their targets - that is, there are several cis-regulatory elements for a single TF or miRNA species in a target gene. Just as the set of TFs in a given cell type has been proposed to constitute a 'code' that specifies cellular differentiation, so 'miRNA codes' are likely to have conceptually similar roles in the specification of cell types.
authors.affiliation: Columbia University Medical Center, Department of Biochemistry & Molecular Biophysics, Center for Neurobiology and Behavior, New York, NY 10032, USA. or38@columbia.edu
authors.forename: Oliver
authors.initials: O
authors.lastname: Hobert
mesh_terms: D000818:Animals; D020650:Combinatorial Chemistry Techniques; D004247:DNA / Q000235:genetics; D005786:Gene Expression Regulation; D035683:MicroRNAs / Q000235:genetics*; D008957:Models, Genetic; D012313:RNA / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D035683:MicroRNAs; D014157:Transcription Factors; D012313:RNA; D004247:DNA