T-cell development by Nanog overexpression. (A) Characterization of T cells in Nanog-thymuses. Almost all (97%) cells in Nanog-thymuses are GFP⁺, whereas approximately half of the cells in the control thymus are GFP⁺. Nanog T cells are CD4⁻CD8⁻ (double negative, DN), CD44⁺CD25⁺, and γδTCR⁺. This phenotype is invariant in all independent experiments. The GFP⁺ cells in the control group consist of T cells from all normal stages. (B) TCR gene rearrangements in 3 clones of Nanog T cells that are isolated from the individual mice 4 months after the reconstitution. In contrast to TCRβ DJ or TCRγ VJ rearrangements, TCRβ V(D)J rearrangement was barely detected. We obtained similar results in 2 other independent experiments. The nomenclature of TCRγ segments is followed by the classification defined by Garman RD nomenclature.³⁷  (C) The time course of the occupancy of thymus by Nanog T cells. The phenotype and cellularity of thymus isolated from the Nanog KSL-reconstituted mice at 1 month, 2 months, and 1 year after reconstitution are shown.