Klf4 interacts directly with Oct4 and Sox2 to promote reprogramming.
Somatic cells can be reprogrammed to induced pluripotent stem (iPS) cells by ectopic expression of specific sets of transcription factors. Oct4, Sox2, and Klf4, factors that share many target genes in embryonic stem (ES) cells, are critical components in various reprogramming protocols. Nevertheless, it remains unclear whether these factors function together or separately in reprogramming. Here we show that Klf4 interacts directly with Oct4 and Sox2 when expressed at levels sufficient to induce iPS cells. Endogenous Klf4 also interacts with Oct4 and Sox2 in iPS cells and in mouse ES cells. The Klf4 C terminus, which contains three tandem zinc fingers, is critical for this interaction and is required for activation of the target gene Nanog. In addition, Klf4 and Oct4 co-occupy the Nanog promoter. A dominant negative mutant of Klf4 can compete with wild-type Klf4 to form defective Oct4/Sox2/Klf4 complexes and strongly inhibit reprogramming. In the absence of Klf4 overexpression, interaction of endogenous Klf4 with Oct4/Sox2 is also required for reprogramming. This study supports the idea that direct interactions between Klf4, Oct4, and Sox2 are critical for somatic cell reprogramming.
Wei
Zong
Z
Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA.
Yang
Yang
Y
Zhang
Peilin
P
Andrianakos
Rosemary
R
Hasegawa
Kouichi
K
Lyu
Jungmook
J
Chen
Xi
X
Bai
Gang
G
Liu
Chunming
C
Pera
Martin
M
Lu
Wange
W
D000818:Animals; D002478:Cells, Cultured; D065150:Cellular Reprogramming; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism*
C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human; C494174:Pou5f1 protein, mouse; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse