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Updated: Aug 12, 2026

Methods to Discover Alternative Promoter Usage and Transcriptional Regulation of Murine Bcrp1
Published on: May 27, 2016
A minimal Bcl-x promoter is activated by Brn-3a and repressed by p53
K L Sugars1, V Budhram-Mahadeo, G Packham
1Medical Molecular Biology Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
Abstract:
The Brn-3a transcription factor stimulates the expression of the anti-apoptotic Bcl-2 and Bcl-x proteins and protects neuronal cells from apoptosis. Here we show that a minimal Bcl-x promoter is activated by Brn-3a and that this stimulation is prevented by the pro-apoptotic p53 protein. Both these effects are mediated via Bcl-x promoter sequences, which are indistinguishable from those required for minimal basal promoter activity. A newly described upstream Bcl-x promoter is also activated by Brn-3a with this activation being prevented by p53. Hence, Brn-3a-mediated activation of two distinct Bcl-x promoters and of the Bcl-2 promoter is blocked by p53 whereas this is not observed for Brn-3a activated promoters derived from genes not involved in inhibiting apoptosis. p53 therefore appears to specifically target the activation by Brn-3a of promoters derived from genes with an anti-apoptotic effect and this may be involved in the pro-apoptotic activity of p53.
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