Functional and chromatin analyses of embryonic stem cell pluripotency by reversible knockdown of bivalent domain regulators
Final Report Abstract
The aim of this work was to study Pcgf6 function in pluripotent cells. We observed that Pcgf6 in contrast to its paralogs was abundantly expressed in undifferentiated ESCs, blastocysts and in testes. Further, we show that in comparison to ESCs cultured under standard conditions, Pcgf6 expression is higher in ESCs cultured in 2i medium and lower in EpiSCs. Upon ESC differentiation, Pcgf6 expression declined. The consequences of Pcgf6 KD in ESCs included reduced colony formation, increased expression of differentiation-associated genes, including mesodermal genes, and increased in vitro ESC hemangioblast-type and hematopoietic differentiation outcomes. Pcgf6, when over-expressed in MEFs together with Oct4, Klf4 and c-Myc, was able to replace Sox2 in the generation of germline-competent iPS cells. OSKM reprogramming of MEFs under Pcgf6 KD resulted in reduced iPS colony numbers. These analyses indicate that Pcgf6 is non-redundantly involved in maintaining the pluripotent nature of ESCs and functions in iPS reprogramming. In summary, we are just beginning to elucidate the role of PRC1 variants in ESC biology and more detailed analyses are required to better understand the relevance of this fascinating and highly elaborate group of chromatin regulators for the pluripotent state. The data shown here are basis for a planned grant application analyzing molecular functions and interaction partners of Pcgf6 in ESCs.
Publications
- Pcgf6, a polycomb group protein, regulates mesodermal lineage differentiation in murine ES cells and functions in iPS reprogramming. Stem Cells 2014, PMID: 25187489
Zdzieblo D, Li X, Lin Q, Zenke M, Illich DJ, Becker M and Müller AM
(See online at https://doi.org/10.1002/stem.1826) - Polycomb protein EED is required for silencing of pluripotency genes upon ESC differentiation. Stem Cell Rev. 2014, PMID: 25134795
Obier N, Lin Q, Cauchy P, Hornich V, Zenke M, Becker M and Müller AM
(See online at https://doi.org/10.1007/s12015-014-9550-z) - PRC1-mediated gene silencing in pluripotent ES cells: function and evolution. Epigenetics and Human Health (series): Epigenetic Mechanisms in Cellular Reprogramming (2014), edited by Alex Meissner and Joern Walter
Becker M, Mah N, Zdzieblo D, Li X, Mer A, Andrade-Navarro MA, Müller AM
(See online at https://doi.org/10.1007/978-3-642-31974-7_7)
