Molecular principles of Oct2-mediated gene activation in B cells.
The octamer motif is a crucial regulatory element for immunoglobulin promoter and enhancer function. We have investigated the molecular mechanisms that underlie octamer-mediated gene activation in B cells. This B cell-specific transcriptional regulation is subject to a novel type of regulatory mechanism. We could demonstrate that octamer-dependent transcription is not only regulated by specific DNA-binding transcription factors, but in addition requires the activity of B cell-restricted cofactors. Both octamer-dependent promoter and enhancer activation depend on such a combination of transcription factor and cofactors. However, the exact requirements differ for these two situations. Promoter activity can be achieved with either one of two distinct transcription factors, Oct1 and/or Oct2, together with the cofactor OCA-B1. In contrast, only Oct2 in conjunction with an additional cofactor, OCA-B2, can confer enhancer activity.
Wirth
T
T
Zentrum für Molekulare Biologie Heidelberg, Germany.
Pfisterer
P
P
Annweiler
A
A
Zwilling
S
S
König
H
H
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D004268:DNA-Binding Proteins; D005786:Gene Expression Regulation / Q000276:immunology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D014157:Transcription Factors