Downregulation of NANOG induces differentiation of human embryonic stem cells to extraembryonic lineages.
The homeobox transcription factor Nanog has been proposed to play a crucial role in the maintenance of the undifferentiated state of murine embryonic stem cells. A human counterpart, NANOG, has been identified, but its function and localization have not hitherto been described. We have used a combination of RNA interference and quantitative real-time polymerase chain reaction to study NANOG in human embryonic stem and embryonic carcinoma cells. Transfection of NANOG-specific small interfering RNAs reduced levels of NANOG transcript and protein and induced activation of the extraembryonic endoderm-associated genes GATA4, GATA6, LAMININ B1, and AFP as well as upregulation of trophectoderm-associated genes CDX2, GATA2, hCG-alpha, and hCG-beta. Immunostaining of preimplantation human embryos showed that NANOG was expressed in the inner cell mass of expanded blastocysts but not in earlier-stage embryos, consistent with a role in the maintenance of pluripotency. Taken together, our findings suggest that NANOG acts as a gatekeeper of pluripotency in human embryonic stem and carcinoma cells by preventing their differentiation to extraembryonic endoderm and trophectoderm lineages.
Centre for Stem Cell Biology and Developmental Genetics, University of Newcastle International Centre for Life, Newcastle NE1 3BZ, United Kingdom.
Louise
L
Hyslop
Miodrag
M
Stojkovic
Lyle
L
Armstrong
Theresia
T
Walter
Petra
P
Stojkovic
Stefan
S
Przyborski
Mary
M
Herbert
Alison
A
Murdoch
Tom
T
Strachan
Majlinda
M
Lako
D001755:Blastocyst / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D045744:Cell Line, Tumor; D019070:Cell Lineage / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D015536:Down-Regulation; D004622:Embryo, Mammalian / Q000166:cytology; D054278:Embryonal Carcinoma Stem Cells; D050991:GATA4 Transcription Factor / Q000378:metabolism; D050993:GATA6 Transcription Factor / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005855:Germ Layers / Q000166:cytology / Q000378:metabolism; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D000071317:Nanog Homeobox Protein; D014411:Neoplastic Stem Cells; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection; D000509:alpha-Fetoproteins / Q000378:metabolism
D004268:DNA-Binding Proteins; D050991:GATA4 Transcription Factor; C484170:GATA4 protein, human; D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D012333:RNA, Messenger; D000509:alpha-Fetoproteins; D049452:Green Fluorescent Proteins