TY  - JOUR
A1  - Peitz, Michael
A1  - Münst, Bernhard
A1  - Thummer, Rajkumar P.
A1  - Helfen, Martina
A1  - Edenhofer, Frank
T1  - Cell-permeant recombinant Nanog protein promotes pluripotency by inhibiting endodermal specification
JF  - Stem Cell Research
N2  - A comprehensive understanding of the functional network of transcription factors establishing and maintaining pluripotency is key for the development of biomedical applications of stem cells. Nanog plays an important role in early development and is essential to induce natural pluripotency in embryonic stem cells (ESCs). Inducible gain-of-function systems allowing a precise control over time and dosage of Nanog activity would be highly desirable to study its vital role in the establishment and maintenance of pluripotency at molecular level. Here we engineered a recombinant cell permeable version of Nanog by fusing it with the cell penetrating peptide TAT. Nanog-TAT can be readily expressed in and purified from E. coli and binds to a consensus Nanog DNA sequence. At cellular level it enhances proliferation and self-renewal of ESCs in the absence of leukemia inhibitory factor (LIF). Nanog-TAT together with LIF acts synergistically as judged by enhanced clonogenicity and activation of an Oct4-promoter-driven GFP reporter gene. Furthermore Nanog-TAT, in the absence of LIF, promotes pluripotency by inhibiting endodermal specification in a Stat3-independent manner. Our results demonstrate that Nanog protein transduction is an attractive tool allowing control over dose and time of addition to the cells for studying the molecular control of pluripotency without genetic manipulation.
KW  - Nanog protein
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-119740
SN  - 1876-7753
VL  - 12
IS  - 3
ER  - 
TY  - JOUR
A1  - Münst, Bernhard
A1  - Thier, Marc Christian
A1  - Winnemöller, Dirk
A1  - Helfen, Martina
A1  - Thummer, Rajkumar P.
A1  - Edenhofer, Frank
T1  - Nanog induces suppression of senescence through downregulation of p27\(^{KIP1}\) expression
JF  - Journal of Cell Science
N2  - A comprehensive analysis of the molecular network of cellular factors establishing and maintaining pluripotency as well as self renewal of pluripotent stem cells is key for further progress in understanding basic stem cell biology. Nanog is necessary for the natural induction of pluripotency in early mammalian development but dispensable for both its maintenance and its artificial induction. To gain further insight into the molecular activity of Nanog, we analyzed the outcomes of Nanog gain-of-function in various cell models employing a recently developed biologically active recombinant cell-permeant protein, Nanog-TAT. We found that Nanog enhances the proliferation of both NIH 3T3 and primary fibroblast cells. Nanog transduction into primary fibroblasts results in suppression of senescence-associated beta-galactosidase activity. Investigation of cell cycle factors revealed that transient activation of Nanog correlates with consistent downregulation of the cell cycle inhibitor p27\(^{KIP1}\) (also known as CDKN1B). By performing chromatin immunoprecipitation analysis, we confirmed bona fide Nanog-binding sites upstream of the p27\(^{KIP1}\) gene, establishing a direct link between physical occupancy and functional regulation. Our data demonstrates that Nanog enhances proliferation of fibroblasts through transcriptional regulation of cell cycle inhibitor p27 gene.
KW  - Embryonic stem cell
KW  - Protein transduction
KW  - Pluripotency
KW  - Senescence
KW  - Cell reprogramming
KW  - p27(KIP1)
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190761
VL  - 129
IS  - 5
ER  -