The opposite and antagonistic effects of the closely related POU family transcription factors Brn-3a and Brn-3b on the activity of a target promoter are dependent on differences in the POU domain.
The Brn-3a, Brn-3b, and Brn-3c POU family transcription factors are closely related to one another and are members of the group IV subfamily of POU factors. Here we show that despite this close relationship, the factors have different effects on the activity of a target promoter: Brn-3a and Brn-3c stimulate the promoter whereas Brn-3b represses it. Moreover, Brn-3b can antagonize the stimulatory effect of Brn-3a on promoter activity and can also inhibit promoter activation by the Oct-2.1 POU factor. The difference in the transactivation activities of Brn-3a and Brn-3b is dependent upon the C-terminal region containing the POU domain of the two proteins, since exchange of this domain between the two factors converts Brn-3a into a repressor and Brn-3b into an activator.
Morris
P J
PJ
Department of Molecular Pathology, University College London Medical School, United Kingdom.
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D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D050809:POU Domain Factors; D027383:Papillomaviridae / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D050818:Transcription Factor Brn-3; D050820:Transcription Factor Brn-3B; D050821:Transcription Factor Brn-3C; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D050809:POU Domain Factors; D011993:Recombinant Fusion Proteins; D050818:Transcription Factor Brn-3; D050820:Transcription Factor Brn-3B; D050821:Transcription Factor Brn-3C; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase