Manipulation of MicroRNAs in Cultured Mouse Embryos: Applications for Developmental Toxicology.

MicroRNAs (miRNAs) are a class of small noncoding RNAs that modulate the expression of virtually all genes. miRNAs have been implicated in the regulation of a broad range of cellular and physiologic processes. Dysregulation of miRNAs has been found to be associated with a variety of diseases and disorders, including teratogenesis. One of the important strategies to reveal miRNA function in teratogenesis is the manipulation of their expression levels and patterns in specific regions in the developing embryos. The combination of microinjection technology with the whole embryo culture (WEC) system provides an excellent platform for the mechanistic study of the roles of miRNAs in teratogenesis. Here we describe an approach to investigating and manipulating miRNAs in cultured mouse embryos and present protocols for whole embryo culture, microinjection of miRNA mimics or inhibitors, validation of the efficacy of microRNA modulation in embryos, and assessment of the teratogen-induced apoptosis.