The Oct-2 glutamine-rich and proline-rich activation domains can synergize with each other or duplicates of themselves to activate transcription.
The B-cell POU homeodomain protein Oct-2 contains two transcriptional activation domains, one N terminal and the other C terminal of the central DNA-binding POU domain. The synergistic action of these two activation domains makes Oct-2 a more potent activator of mRNA promoters than the related broadly expressed octamer motif-binding protein Oct-1, which contains an N-terminal but not a C-terminal Oct-2-like activation domain. Both Oct-2 mRNA promoter activation domains were delineated by truncation analysis: the N-terminal Q domain is a 66-amino-acid region rich in glutamines, and the C-terminal P domain is a 42-amino-acid region rich in prolines. The Q and P domains synergized with each other or duplicates of themselves, independently of their N-terminal or C-terminal position relative to the POU domain. The C-terminal P domain, which differentiates Oct-2 from Oct-1, also activated transcription in conjunction with the heterologous GAL4 DNA-binding domain. Oct-2 thus contains three modular functional units, the DNA-binding POU domain and the two P and Q activation domains. An electrophoretic mobility shift assay with a variety of these Oct-2 activators revealed a distinct complex called QA that was dependent on the presence of an active glutamine-rich activation domain and migrated more slowly than the Oct-2-DNA complexes. Formation of the QA complex is consistent with interaction of the glutamine-rich activation domains with a regulatory protein important for the process of transcriptional activation.
Tanaka
M
M
Cold Spring Harbor Laboratory, New York 11724.
Clouston
W M
WM
Herr
W
W
D000595:Amino Acid Sequence; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D005656:Fungal Proteins; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D050813:Octamer Transcription Factor-2; D015345:Oligonucleotide Probes / Q000737:chemistry; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D050813:Octamer Transcription Factor-2; D015345:Oligonucleotide Probes; C058435:POU2F2 protein, human; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors