Effect of Foxd1 knockdown in the reprogramming process

It remains unclear how the ectopic expression of defined transcription factors induces dynamic changes in gene expression profiles that establish a pluripotent state during direct cell reprogramming. In the present study, we first identified a temporal gene expression program during the reprogramming process. Promoter analyses then predicted the role of two forkhead box transcription factors, Foxd1 and Foxo1, as mediators of the gene expression program. Knockdown of Foxd1 or Foxo1 reduced the number of induced pluripotent stem cells (iPSCs). The knockout of Foxd1 prevented the downstream transcription program, including the expression of reprogramming marker genes. Interestingly, the expression level of Foxd1 was also transiently increased in a small population of cells in the middle stage of reprogramming. The presence or absence of Foxd1 expression in this stage was correlated with a future cell fate as iPSCs or non-reprogrammed cells. These results suggest that Foxd1 is a mediator and indicator of the successful progression of the gene expression program in cell reprogramming.

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Koga M, Matsuda M, Kawamura T, Sogo T, Shigeno A, Nishida E, Ebisuya M