Enforced ISG15 expression facilitates erythroid terminal differentiation.

<p>(<b>A</b>) Western blot analysis of whole cell extract obtained from proliferating p53^-/- erythroid cell line transduced with either the control MSCV-puro, or MSCV-puro-ISG15-flag retroviruses. An anti-ISG15 antibody was used to show ISG15 expression and induction of protein ISGylation on a 10% acrylamide gel while anti-STAT5 was used as a loading control. (<b>B</b>) Hemoglobin content quantification analyses 48 and 72 hours after differentiation induction. (<b>C</b>) Quantification of cytospin preparation of 48 h-differentiating control and ISG15-overexpressing erythroblasts. Cells (≥200) were counted per slide and mean values ±s.d. calculated from at least three independent experiments (<b>D</b>) Flow cytometry analysis of erythroid cell surface marker Ter119, 72 hours after differentiation induction. Grey line: isotypic control, grey dashed line: control proliferating erythroblasts (1,34% Ter119 positive cells), black dashed line: control differentiating erythroblasts (24,2% Ter119 positive cells); black line: ISG15-differentiating erythroblasts (34,4% Ter119 positive cells).