Constructing suprachiasmatic nucleus chimeras in vivo

We introduce a new transplantation technique for analyzing suprachiasmatic nucleus (SCN) development and function. Neural precursor ('stem') cells are harvested from the brains of mice engineered to express the green fluoresc ent protein, propagated in culture with growth factors, and injected into t he forebrain ventricles of individual embryos in order to gain access to th e ventricular germinal zone and the developing brain. Initial data indicate that such cells can incorporate within the SCN and appear to differentiate into astroglial phenotypes. In addition to applications in chronobiology, SCN chimeras may be a potentially powerful model system for analyzing the s tructural and functional plasticity of implanted precursor cells.