Increased efficiency in the generation of induced pluripotent stem cells by Fbxw7 ablation.
Induced pluripotent stem cells (iPSCs) share many biological properties with embryonic stem cells (ESCs), and are generated from somatic cells by expression of some transcription factors such as Oct3/4, Sox2, Klf4 and c-Myc. Among these factors, the abundance of c-Myc is strictly regulated by Fbxw7, a subunit of Skp1-Cul1-F-box protein-type ubiquitin ligase. We have now shown that the expression of Fbxw7 was increased as ESCs differentiated. To investigate the role of Fbxw7 in the ESCs/iPSCs, we examined the impact of Fbxw7 ablation in the efficiency in iPSC generation. The frequency of iPSC generation from mouse embryonic fibroblasts (MEFs) lacking Fbxw7 was markedly greater than that from control MEFs. Depletion of Fbxw7 also resulted in promotion of iPSC generation. Morphology of iPSC clonies from Fbxw7-depleted MEFs appeared more undifferentiated than that from MEFs overexpressing c-Myc. Additional depletion of c-Myc did not abrogate the effect of Fbxw7 depletion, suggesting that c-Myc accumulation is not necessarily required for the increased efficiency in iPSC generation by Fbxw7 ablation. Substrates of Fbxw7 other than c-Myc might therefore play a key role in iPSC generation. These results suggest that transient inhibition of Fbxw7 would be a more promising approach to efficient generation of iPSCs than c-Myc over-expression.
Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
Yasutaka
Y
Okita
Akinobu
A
Matsumoto
Kanae
K
Yumimoto
Rieko
R
Isoshita
Keiichi I
KI
Nakayama
D000818:Animals; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D000073979:F-Box-WD Repeat-Containing Protein 7; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D017353:Gene Deletion; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D000090062:Kruppel-Like Factor 4; D051379:Mice; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014212:Tretinoin / Q000494:pharmacology; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; C513272:Fbxw7 protein, mouse; D018398:Homeodomain Proteins; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; C489428:Myc protein, mouse; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D014212:Tretinoin; D044767:Ubiquitin-Protein Ligases