Differential regulation of the Oct-3/4 gene in cell culture model systems that parallel different stages of mammalian development.
Oct-3/4 is an essential transcription factor that regulates stem cell fate during embryogenesis. Previous reports have shown that the Oct-3/4 gene utilizes different enhancers to regulate its expression as development proceeds. However, the cis-elements contributing to the differential activity of these enhancers require further study. Here, we investigated the function of the HMG/POU cassette and LRH-1 site present in the distal enhancer (DE) and the proximal enhancer, respectively. F9 and P19 EC cells were the focus of this study because their differential utilization of Oct-3/4 enhancers parallels the use of these enhancers during different stages of development. We determined that the LRH-1 site functions as a positive and a negative cis-regulatory element in P19 and F9 EC cells, respectively. Furthermore, we determined that the HMG/POU cassette in the DE strongly activates the Oct-3/4 promoter in F9 cells, but is a much weaker positive regulatory element in P19 cells. Given that HMG/POU cassettes play key roles in the regulation of at least seven essential genes, the Oct-3/4 HMG/POU cassette was examined more closely by focusing on Sox2, which can bind to HMG/POU cassettes. Although chromatin immunoprecipitation demonstrated that Sox2 binds to the Oct-3/4 gene equally well in both EC cell lines, tethering Sox2 to the region of the HMG/POU cassette only activated the Oct-3/4 promoter in F9 EC cells. These and other findings suggest that the differential activity of the HMG/POU cassette of the Oct-3/4 gene in EC cells is due to differential action of Sox2 and its associated co-factors.
Mallanna
Sunil Kumar
SK
Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA.
Boer
Brian
B
Desler
Michelle
M
Rizzino
Angie
A
D000818:Animals; D015152:Blotting, Northern; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000235:genetics; D040461:Gene Components; D018507:Gene Expression Regulation, Developmental; D024002:HMGB Proteins / Q000378:metabolism; D051379:Mice; D050814:Octamer Transcription Factor-3 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors; D014157:Transcription Factors / Q000378:metabolism
D017931:DNA Primers; D004268:DNA-Binding Proteins; D024002:HMGB Proteins; D050814:Octamer Transcription Factor-3; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D014157:Transcription Factors