A novel octamer binding transcription factor is differentially expressed in mouse embryonic cells.
We have identified a novel octamer binding factor (Oct-3) in P19 embryonal carcinoma cells. Oct-3, which recognizes the typical octamer motif (ATTTGCAT) as well as the AT-rich sequence TTAAAATTCA, is present in P19 stem cells but disappears when the cells are induced to differentiate by retinoic acid (RA). Cloned cDNA corresponding to Oct-3 encodes a protein of 377 amino acids. Oct-3 has a conserved POU domain, but the remaining part is distinct from other POU domain-containing proteins such as Oct-1 and Oct-2. mRNA of 1.5 kb coding for Oct-3 is abundant in P19 stem cells but is dramatically repressed during RA-induced differentiation. Repression of the 1.5 kb mRNA is rapid and specific to RA. In mouse, oct-3 mRNA is undetectable in all the adult organs examined. The N-terminal proline-rich region of Oct-3, when fused to the DNA binding domain of c-Jun, functions as a transcriptional activating domain. We suggest that Oct-3 is a novel octamer binding transcription factor that is developmentally regulated during mouse embryogenesis.
Okamoto
K
K
Department of Biochemistry, Faculty of Medicine, University of Tokyo, Japan.
Okazawa
H
H
Okuda
A
A
Sakai
M
M
Muramatsu
M
M
Hamada
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D015723:Gene Library; D005801:Genes, Homeobox; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D050814:Octamer Transcription Factor-3; D015345:Oligonucleotide Probes; D010957:Plasmids; D014176:Protein Biosynthesis; D012334:RNA, Neoplasm / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D013724:Teratoma; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D050814:Octamer Transcription Factor-3; D015345:Oligonucleotide Probes; D012334:RNA, Neoplasm; D014157:Transcription Factors