Promyelocytic Leukemia (PML) Involves Cellular Pluripotency and Neural Development

Promyelocytic leukemia (PML) is one of the major proteins in the PML nuclear bodies (PML-NBs). Retinoic acid (RA) exerts its tumor growth suppressor activity and terminal myeloid differentiation of granulocyte/monocyte progenitor (GMP) cells throught PML-NBs in the RA pathway. RA acts as a natural morphogen during posterior patterning in embryo neural development. This study was aimed to define the possible PML involvemet in RA dependent neural development of human embryonic stem cells (hESCs). The expression level of PML at both mRNA and protein level was assessed by the quantitative real time RT-PCR (q-RT-PCR) and western blotting, respectively. The mRNA data showed that PML had maximum expression in pluripotent hESCs and this expression clearly decreased in neural precursor cells (hNPCs) and neural cells (hNCs). No significant differences existed between the two latter cell types at mRNA level, while protein assay showed numerous protein bands with different intensities in hESCs, hNPCs, and hNCs. The data suggest that PML may have an important role in cellular pluripotency, and PML might be necessary in cellular pluripotency and nervous system development.