Double In Utero Electroporation to Target Temporally and Spatially Separated Cell Populations.

In utero electroporation is an in vivo DNA transfer technique extensively used to study the molecular and cellular mechanisms underlying mammalian corticogenesis. This procedure takes advantage of the brain ventricles to allow the introduction of DNA of interest and uses a pair of electrodes to direct the entrance of the genetic material into the cells lining the ventricle, the neural stem cells. This method allows researchers to label the desired cells and/or manipulate the expression of genes of interest in those cells. It has multiple applications, including assays targeting neuronal migration, lineage tracing, and axonal pathfinding. An important feature of this method is its temporal and regional control, allowing circumvention of potential problems related with embryonic lethality or the lack of specific CRE driver mice. Another relevant aspect of this technique is that it helps to considerably reduce the economic and temporal limitations that involve the generation of new mouse lines, which become particularly important in the study of interactions between cell types that originate in distant areas of the brain at different developmental ages. Here we describe a double electroporation strategy that enables targeting of cell populations that are spatially and temporally separated. With this approach we can label different subtypes of cells in different locations with selected fluorescent proteins to visualize them, and/or we can manipulate genes of interest expressed by these different cells at the appropriate times. This strategy enhances the potential of in utero electroporation and provides a powerful tool to study the behavior of temporally and spatially separated cell populations that migrate to establish close contacts, as well as long-range interactions through axonal projections, reducing temporal and economic costs.