A nexus between Oct-4 and E1A: implications for gene regulation in embryonic stem cells.
Oct-4 is a transcription factor expressed in the pluripotent progenitor cells of the early mouse embryo. Additional factors are required for the distal activation of genes in differentiated cells containing ectopically expressed Oct-4. Here we show that Oct-4 and E1A are sufficient for distance-independent activation of the basal transcription machinery. The ratio of Oct-4 to E1A is critical for transcriptional activation, because higher levels of either factor are less efficient. Activation depends on a transactivation domain linked to the POU domain of Oct-4 and also on the conserved domain 3 of the 289RE1A protein. This domain is required for binding to the C-terminal part of Oct-4 including the POU domain. Our results indicate that E1A can serve as a bridging factor between Oct-4 and the basal initiation complex, and we postulate that an E1A-like factor acts as a cellular bridging factor of Oct-4 in pluripotent cells.
Schöler
H R
HR
Department of Molecular Cell Biology, Max Planck Institute of Biophysical Chemistry, Göttingen, Federal Republic of Germany.
Ciesiolka
T
T
Gruss
P
P
D017456:Adenovirus Early Proteins; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors; D006367:HeLa Cells / Q000502:physiology; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D050814:Octamer Transcription Factor-3; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D013724:Teratoma; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection
D017456:Adenovirus Early Proteins; D004268:DNA-Binding Proteins; D050814:Octamer Transcription Factor-3; D009856:Oncogene Proteins, Viral; C494173:POU5F1 protein, human; C494174:Pou5f1 protein, mouse; D014157:Transcription Factors