Comparative analysis of human, bovine, and murine Oct-4 upstream promoter sequences

The Oct-4 gene encodes a transcription factor that is specifically expresse d in embryonic stem cells and germ cells of the mouse embryo. Cells that di fferentiate into somatic tissues lose Oct-4 expression. Regulation of Oct-4 gene transcription involves a TATA-less minimal promoter and two upstream elements: the proximal (PE) and distal enhancers (DE). We report here the n ucleotide sequence of the 5' upstream regulatory regions of the human and m urine Oct-4 genes. A comparative alignment analysis between these regions a nd those of the bovine Oct-4 ortholog reveals four conserved regions of hom ology (CR 1 to 4) between these species (66-94% conservation). The 1A seque nce within the mouse PE is located approximately half-way between CR 2 and CR 3. A putative Sp1/Sp3 binding site and the overlapping hormone responsiv e element (HRE) in CR I are identical in all three species. A high number o f CCC(A/T)CCC motifs exhibit various levels of homology in these upstream r egions. We discuss the importance of these and other sequences and present candidate factors that may bind and regulate Oct-4 gene expression.