Identification of Tmem10/Opalin as a novel marker for oligodendrocytes using gene expression profiling. Mus musculus

Background During the development of the central nervous system, oligodendrocytes generate large amounts of myelin, a multilayered insulating membrane that ensheathes axons, thereby allowing the fast conduction of the action potential and maintaining axonal integrity. Differentiation of oligodendrocytes to myelin-forming cells requires the downregulation of RhoA GTPase activity. Results To gain insights into the molecular mechanisms of oligodendrocyte differentiation, we performed microarray expression profiling of the oligodendroglial cell line, Oli-neu, treated with the Rho kinase (ROCK) inhibitor, Y-27632 or with conditioned neuronal medium. This resulted in the identification of the transmembrane protein 10 (Tmem10/Opalin), a novel type I transmembrane protein enriched in differentiating oligodendrocytes. In primary cultures, Tmem10 was abundantly expressed in O4-positive oligodendrocytes, but not in oligodendroglial precursor cells, astrocytes, microglia or neurons. In mature oligodendrocytes Tmem10 was enriched in the rims and processes of the cells and was only found to a lesser extent in the membrane sheets. Conclusions Together, our results demonstrate that Tmem10 is a novel marker for in vitro generated oligodendrocytes. Keywords: gene expression profiling for oligodendrocytes, olineu, oligodendrocyte differentiation Overall design: 2 Subexperiments: 1. olineu in absence of neurons (control) vs. olineu in presence of neurons including dye swap design with 6 technical replicates 2. olineu in presence of neurons (control) vs. Y27631 treated olineu in presence of neurons