Biochemical and Biophysical Research Communications, Vol.431, No.2, 225-231, 2013
Heterochromatin protein 1 gamma overexpression in P19 embryonal carcinoma cells elicits spontaneous differentiation into the three germ layers
P19 embryonal carcinoma (EC) cells are pluripotent stem cells and have numerous morphological and biochemical properties in common with embryonic stem (ES) cells. However, P19 cells differentiate very ineffectively as embryoid bodies (EBs) without the specific chemical inducers whereas ES cells exhibit spontaneous differentiation to the three germ layers. Recently the heterochromatin protein 1 (HP1) family protein HP1 gamma, which is an epigenetic modulator that binds histone H3 methylated at lysine 9, is shown to be associated with the progression from pluripotent to differentiated status in ES cells. Therefore, to study the role of HP1 gamma in the differentiation capacity of P19 cells, we have established a HP1 gamma-over-expressing P19 cell line (HP1 gamma-P19). Similar to the parental P19 cells, undifferentiated HP1 gamma-P19 cells continued to express pluripotency marker genes. However, HP1 gamma-P19 cells exhibited significant morphological differentiation including beating cardiomyocytes, as well as Tuj1-positive neuronal cells and Sox17-positive endodermal cells after EB formation under a normal culture condition. Moreover, real-time RT-qPCR analysis revealed that HP1 gamma-P19 EB cells expressed various differentiation marker genes. Thus, HP1 gamma-P19 cells could give rise to all three germ layers in EBs without any drug treatment. Therefore, HP1 gamma affects the spontaneous differentiation potential of P19 cells, and might play major roles in the decision of cell fates in pluripotent stem cells. (C) 2013 Elsevier Inc. All rights reserved.