Fig. 1.

Paraxial mesoderm induction in a Tbx6 and Brachyury dual reporter mouse ESC model. (A) DNA maps of reporter genes and mesoderm differentiation strategy. Tbx6-H2B-EYFP was targeted into the endogenous gene locus as previously described [1]. The Brachyury-Cherry reporter was introduced into ESCs as a BAC transgene. Established stem cells were plated for differentiation and allowed to adjust to the base differentiation media for two days, followed by four days of differentiation with mesoderm inducing factors. (B-E) Imaging of Tbx6 (green) and Brachyury (red) reporter expression during ESC differentiation in réponse to Wnt3a and CHIR99021 from days 2 to 6. (C1-C3) Imaging of reporter expression at higher magnification on day 4 suggests that Tbx6⁺ and Brachyury⁺ cells are largely distinct populations. (F) Gene expression analyses on sorted cell populations confirms the fidelity of reporter expression with endogenous gene expression and enrichment of paraxial mesoderm genes in the Tbx6⁺ population. Data shown as mean ± SEM (n = 3, *p < .05, where * denotes the comparison of T⁺ to Tbx6⁺). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)