Immunohistochemical analysis by laser confocal microscopy of gene expression by CTO-labeled cultured CD34+, Sca-1+, AA4.1+, and cKit+ adult C57BL/6J mouse bone marrow cells transplanted into adult C57BL/6J mouse brain hippocampus and striatum. First row, CTO-labeled cells continue to express CD34 6 weeks after implantation into adult brain, and host brain cells fail to express CD34. Second row, oligodendroglial CNPase (transplanted cell, arrowhead; host cell, arrow). Third and fourth rows, astroglial GFAP (transplanted cell, arrowhead; host cell, arrow). Fifth and sixth rows, neuronal neurofilament H. Seventh row, NeuN expression in CTO-labeled adult mouse bone marrow cells 1 year after implantation into adult mouse brain. The last three rows show that transplanted CTO-labeled cells express either astroglial (GFAP) or neuronal (neurofilament H and NeuN) proteins but not both; arrows show the same cell in each row triple-labeled 1 year after implantation.