text: The Expression Pattern of Sox6 Suggests a Role in Definitive Erythropoiesis
  The observation that Sox6-deficient mice ectopically express epsilony globin in liver, where definitive erythroid cells mature, suggests that Sox6 is an important regulator in definitive erythropoiesis. To determine the temporal and spatial expression pattern of Sox6, Northern blot and in situ hybridization assays were employed. As shown in Figure 6A, Sox6 is detectable by Northern blot beginning at 10.5 dpc, coincident with the temporal onset of definitive erythropoiesis in the liver. Furthermore, in situ hybridization shows that Sox6 is highly transcribed in 12.5-dpc liver, but not in yolk sac blood islands at 7.5 dpc (Figure 6B). Therefore, Sox6 expression is temporally and spatially coincident with definitive, but not primitive, erythropoiesis. These data, taken together with the observation that epsilony globin is highly expressed in the liver cells of 14.5-dpc p100H mutant mice (Figure 5), demonstrate that Sox6 functions in definitive erythropoiesis. 
  