Screening of Human cDNA Library Reveals Two differentiation-Related Genes, HHEX and HLX, as Promoters of Early Phase Reprogramming toward Pluripotency

Stem Cells. 2016 Nov;34(11):2661-2669. doi: 10.1002/stem.2436. Epub 2016 Jul 8.


Gene screenings have identified a number of reprogramming factors that induce pluripotency from somatic cells. However, the screening methods have mostly considered only factors that maintain pluripotency in embryonic stem cells, ignoring a potentially long list of other contributing factors involved. To expand the search, we developed a new screening method that examined 2,008 human genes in the generation of human induced pluripotent stem cells (iPSCs), including not only pluripotent genes but also differentiation-related genes that suppress pluripotency. We found the top 100 genes that increased reprogramming efficiency and discovered they contained many differentiation-related genes and homeobox genes. We selected two, HHEX and HLX, for further analysis. These genes enhanced the appearance of premature reprograming cells in the early phase of human iPSC induction, but had inhibitory effect on the late phase. In addition, when expressed in human iPSCs, HHEX and HLX interfered with the pluripotent state, indicating inverse effects on somatic reprograming and pluripotent maintenance. These results demonstrate that our screening is useful for identifying differentiation-related genes in somatic reprograming. Stem Cells 2016;34:2661-2669.

Keywords: HHEX; HLX; Human cDNA library; Induced pluripotent stem cell; Reprogramming; Screening.

MeSH terms

  • Animals
  • Cell Differentiation
  • Cell Line
  • Cellular Reprogramming*
  • Fibroblasts / cytology
  • Fibroblasts / metabolism*
  • Gene Expression Profiling
  • Gene Expression Regulation
  • Gene Library*
  • High-Throughput Screening Assays
  • Homeodomain Proteins / genetics*
  • Homeodomain Proteins / metabolism
  • Humans
  • Induced Pluripotent Stem Cells / cytology
  • Induced Pluripotent Stem Cells / metabolism*
  • Kruppel-Like Factor 4
  • Kruppel-Like Transcription Factors / genetics
  • Kruppel-Like Transcription Factors / metabolism
  • Leukocytes, Mononuclear / cytology
  • Leukocytes, Mononuclear / metabolism
  • Mice
  • Mouse Embryonic Stem Cells / cytology
  • Mouse Embryonic Stem Cells / metabolism
  • Octamer Transcription Factor-3 / genetics
  • Octamer Transcription Factor-3 / metabolism
  • Plasmids / chemistry
  • Plasmids / metabolism
  • Primary Cell Culture
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism
  • SOXB1 Transcription Factors / genetics
  • SOXB1 Transcription Factors / metabolism
  • Time Factors
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Transfection


  • HHEX protein, human
  • HLX protein, human
  • Homeodomain Proteins
  • Kruppel-Like Factor 4
  • Kruppel-Like Transcription Factors
  • MYCL protein, human
  • Octamer Transcription Factor-3
  • POU5F1 protein, human
  • Proto-Oncogene Proteins c-myc
  • SOX2 protein, human
  • SOXB1 Transcription Factors
  • Transcription Factors