Two potent transactivation domains in the C-terminal region of human NANOG mediate transcriptional activation in human embryonic carcinoma cells.
The core embryonic stem cell transcription factors Oct4, Sox2, and Nanog are expressed in germ cell tumors (GCTs) and have been proposed to play a regulatory role in tumorigenesis. However, little is known about the mechanism of regulation of tumorigenesis by the complicated network of these proteins. Nanog is a novel homeobox-containing transcription factor that is expressed in pluripotent cells as well as GCTs. To understand the molecular and functional role of human NANOG (hNANOG) in germ cells, mutagenesis of the C-terminal domain (CD) of hNANOG and transient transfection assays in NCCIT human embryonic carcinoma cells were carried out to identify critical transactivation motifs. We divided the CD into three putative functional subdomains, CD1, tryptophan-repeat (WR) subdomain, and CD2. WR subdomain and CD2 independently contained transcriptional potential and, in combination, had a synergistic effect on transcriptional activity, while CD1 was transcriptionally inactive. The glutamine (Q) motif in WR subdomain, and multiple acidic residues in CD2 were required for maximal and synergistic transcriptional activation by the hNANOG CD. The results of the current study contribute to a better understanding of the complicated molecular machinery of stem cell transcription factors and their role in unregulated proliferation in germ cell tumorigenesis.
Do
Hyun-Jin
HJ
Graduate School of Life Science & Biotechnology, Pochon CHA University, Seoul 135-907, South Korea.
Lee
Won-Young
WY
Lim
Hye-Young
HY
Oh
Jong-Hyun
JH
Kim
Dong-Ku
DK
Kim
Jin-Hoi
JH
Kim
Teoan
T
Kim
Jae-Hwan
JH
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D054278:Embryonal Carcinoma Stem Cells / Q000166:cytology / Q000502:physiology*; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D000071317:Nanog Homeobox Protein; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015533:Transcriptional Activation
D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D011993:Recombinant Fusion Proteins