Figure 1.

Global gene expression profiling reveals Tbx3 aids cell fusion-mediated reprogramming. (A) Modified ESCs with Nanog over-expression (OE) or Tcf3 RNAi were fused with MEFs to generate tetraploid ESC/MEF hybrids resistant to neomycin and puromycin. (B) Nanog OE, Tbx3 OE and Tcf3 RNAi enhanced cell fusion-mediated reprogramming of MEFs. Representative examples illustrate the emergence of ESC/MEF hybrid colonies. Control ESC fusion with MEFs resulted in an average of one per experiment whereas Tcf3 RNAi, Nanog OE or Tbx3 OE ESCs produced numerous hybrid clones. (C) Nanog OE ESCs were efficient in reprogramming MEFs, generating 13 colonies, followed by Tcf3 RNAi (10) and Tbx3 OE (4.5). The numbers represent the average of four independent fusion experiments. * denotes significantly different from vector, ⁺ denotes significantly different from control shRNA; error bars represent s.e.m. (D) The heat-map shows all genes which were increased in treated ESCs compared to controls. Tbx3 was among the most highly up-regulated genes in Nanog OE and Tcf3 RNAi ESCs. The left-most column in red indicates direct gene targets of Nanog or Tcf3 based on the ChIP-PET²¹ and ChIP-chip¹³ databases respectively. (E) RNAi knockdown of Tbx3 in ESCs led to a loss of self-renewal and induced differentiation. Scale bar = 100 μm. (F) Enrichment of Tcf3 and Nanog occupancy on the Tbx3 gene, as measured by ChIP-qPCR.