Figure 6. DCK Ser⁷⁴ influences T cell development.

(A) Western blot of CD45.2⁺ dCK KO cells (YFP⁻) carrying one of three dCK isoforms (WT, S74A, S74E; YFP⁺). Cells were isolated from recipient spleens and dCK expression level compared to endogenous dCK of CD45.1⁺ B6.SJL recipient. (B) In vitro dCK kinase assay using [³H]-dC and lysates of dCK KO donor CD45.2⁺ (dCK⁺YFP⁺ or dCK⁻YFP⁻) cells FACS purified from spleens of B6.SJL recipients (N = 3 mice per group). (C) Cellularity of B6.SJL thymi repopulated with dCK KO donor cells carrying different dCK isoforms (CD45.2⁺YFP⁺; N = 3). (D) FACS analysis of dCK KO ± dCK (WT, S74A, S74E) thymocytes. Bottom panels show pSer¹³⁹ γH2A.X stained DN3 thymocytes. (E-F) Averaged percentages of single live donor CD45.2⁺ thymocytes (± dCK/YFP) at different stages of development (N = 3). (G) Averaged percentages of DN3 thymocytes positive for pSer¹³⁹ γH2A.X (N = 3).