| Studying the development of the mammalian central nervous system has been a great challenge because of its complexity and the difficulty in finding appropriate model systems. Through years of research, many protein makers have been identified and associated with certain neural lineages at specific developmental stage. However, the specificity and reliability of many protein markers used have been challenged in recent years. The transmembrane protein, neural-glial 2 (NG2), has been considered the cellular marker expressed in oligodendrocyte precursor cells (OLPs), but recent reports have suggested that postnatal NG2+ OLPs have multiple cell fates. To conclusively determine the differentiation potentials of NG2+ OLPs, I applied Cre/LoxP lineage tracing strategy starting with generating the NG2-Cre transgenic mouse line with using the BAC transgenic method. The NG2-Cre mice were then crossed with the reporter mouse line, Rosa26LacZ. By tracing the expression of transgene, I have confirmed that NG2+ progenitor cells are capable to generate all three neural cell lineages instead of one as previously believed. Furthermore, lineage tracing of NG2 progenitors also indicated that the cell lineage determination is partially controlled by microenvironmental factors, since NG2 progenitors' differentiation potential is region specific. Although, microenvironmental stimulation is critical for cell differentiation, but it did not seem to be the only factor that influence cell specification. By comparing two double transgenic mouse lines, (NG2-Cre/Rosa26LacZ and Gfap-Cre/Rosa26LacZ), I have found that both NG2 and GFAP progenitor cells can give rise to granule neurons in the dentate gyms, but the terminal location of two neuronal populations were distinctively generated. |
