Abstract: MicroRNAs (miRNAs) are the class of noncoding single-stranded RNA molecules composed of approximately 20–24 nucleotides. These small miRNAs bind to complementary sequences in the 3' untranslated region (UTR) of mRNAs to negatively regulate gene expression. Bone organogenesis is a complex process, which involves the differentiation and crosstalk of multiple cell types for formation and remodeling of the skeleton. The existing evidence indicates that miRNAs control multiple layers of gene regulation for bone development and postnatal functions. Currently, inhibition of mRNA translation by miRNAs has been regarded as an important regulator for bone development and homeostasis. This review focuses on the current knowledge of miRNAs and their involvement in the regulation of bone formation and bone resorption.

Key words: microRNA, osteoblasts, osteoclasts