Reprogramming capacity of Nanog is functionally conserved in vertebrates and resides in a unique homeodomain.
Pluripotency is a developmental ground state that can be recreated by direct reprogramming. Establishment of pluripotency is crucially dependent on the homeodomain-containing transcription factor Nanog. Compared with other pluripotency-associated genes, however, Nanog shows relatively low sequence conservation. Here, we investigated whether Nanog orthologs have the capacity to orchestrate establishment of pluripotency in Nanog(-/-) somatic cells. Mammalian, avian and teleost orthologs of Nanog enabled efficient reprogramming to full pluripotency, despite sharing as little as 13% sequence identity with mouse Nanog. Nanog orthologs supported self-renewal of pluripotent cells in the absence of leukemia inhibitory factor, and directly regulated mouse Nanog target genes. Related homeodomain transcription factors showed no reprogramming activity. Nanog is distinguished by the presence of two unique residues in the DNA recognition helix of its homeodomain, and mutations in these positions impaired reprogramming. On the basis of genome analysis and homeodomain identity, we propose that Nanog is a vertebrate innovation, which shared an ancestor with the Bsx gene family prior to the vertebrate radiation. However, cephalochordate Bsx did not have the capacity to replace mouse Nanog in reprogramming. Surprisingly, the Nanog homeodomain, a short sequence that contains the only recognizable conservation between Nanog orthologs, was sufficient to induce naive pluripotency in Nanog(-/-) somatic cells. This shows that control of the pluripotent state resides within a unique DNA-binding domain, which appeared at least 450 million years ago in a common ancestor of vertebrates. Our results support the hypothesis that naive pluripotency is a generic feature of vertebrate development.
Wellcome Trust Centre for Stem Cell Research and Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK.
Thorold W
TW
Theunissen
Yael
Y
Costa
Aliaksandra
A
Radzisheuskaya
Anouk L
AL
van Oosten
Fabrice
F
Lavial
Bertrand
B
Pain
L Filipe C
LF
Castro
José C R
JC
Silva
D000595:Amino Acid Sequence; D000818:Animals; D065150:Cellular Reprogramming / Q000235:genetics*; D017124:Conserved Sequence; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox / Q000502:physiology; D018398:Homeodomain Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008954:Models, Biological; D008969:Molecular Sequence Data; D000071317:Nanog Homeobox Protein; D010802:Phylogeny; D017434:Protein Structure, Tertiary / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014714:Vertebrates / Q000235:genetics*
D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse