The ability of the inhibitory domain of the POU family transcription factor Oct-2 to interfere with promoter activation by different classes of activation domains is dependent upon the nature of the basal promoter elements.
The Oct-2 transcription factor contains an inhibitory domain which is able to repress transcription following DNA binding. Here we show that within the neuronally expressed Oct-2.5 form, the inhibitory domain can strongly inhibit activation by transcription factor activation domains which are either composed predominantly of acidic residues or contain the HOB motif, whereas it has a weaker effect or no effect on proline-rich activation domains and on a glutamine-rich domain. In contrast, the isolated inhibitory domain of Oct-2 can efficiently repress all types of activation domains. This effect is observed however, only on TATA box-containing promoters and not on promoters containing an initiator motif. This widespread inhibition of different activation domains and its dependence on the nature of the basal promoter elements indicate that the inhibitory domain is likely to act by contacting a common downstream target of activation domains within the basal transcriptional complex bound at the TATA box rather than quenching specific activation domains by direct interaction. These effects are discussed in terms of the functional role of the inhibitory domain within Oct-2.5 and the mechanism by which it acts.
Liu
Y Z
YZ
Department of Molecular Pathology, University College London Medical School, London W1P 6DB, United Kingdom.
Dawson
S J
SJ
Gerster
T
T
Friedl
E
E
Pengue
G
G
Matthias
P
P
Lania
L
L
Latchman
D S
DS
D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics; D005786:Gene Expression Regulation; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins; D012097:Repressor Proteins / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors