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Differential regulation of the Oct‐3/4 gene in cell culture model systems that parallel different stages of mammalian development
Author(s) -
Mallanna Sunil Kumar,
Boer Brian,
Desler Michelle,
Rizzino Angie
Publication year - 2008
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20871
Subject(s) - pou domain , enhancer , biology , sox2 , transcription factor , microbiology and biotechnology , gene , genetics , homeobox
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. Mol. Reprod. Dev. 75: 1247–1257, 2008. © 2008 Wiley‐Liss, Inc.