Electroporation in the developing mouse olfactory bulb

In utero electroporation is a method to deliver DNA into the developing mouse brain. The technique is very useful to study the mechanisms of mammalian brain development, and now has been widely applied to many brain regions and species since the method was first reported by Saito and Nakatsuji in 2001. Here, we provide a protocol for applying in utero electroporation to the developing mouse olfactory bulb (OB). The target cells of this protocol in the OB are the projection neurons, especially mitral cells. By introducing different plasmids, our method allows us to follow the developmental changes of mitral cell location and morphology in the presumptive OB of the embryonic mouse brain, and to study functions of specific molecules in developing mitral cells. Mitral cells are generated during a narrow temporal window in the embryonic brain, and unfortunately, there are few effective gene-targeted or transgenic mouse lines for studying the development of OB projection neurons. The electroporation technique we describe here can overcome these disadvantages, and therefore, will facilitate the study of the molecular mechanisms regulating mitral cell development. In utero electroporation that can be used to track mitral cell migration and differentiation as well as to upregulate or downregulate the candidate developmental molecules will lead us to a deeper understanding of organization within the olfactory system and the strategies it employs for processing odor information.