Retinoblastoma susceptibility gene product pRB activates hypoxia-inducible factor-1 (HIF-1).
Hypoxia-inducible factor-1 alpha (HIF-1alpha) constitutes a regulatory subunit of HIF-1, a major transcriptional activator of genes that coordinate physiological and pathological responses towards hypoxia. In order to identify novel interaction partners of HIF-1alpha we have applied T7 phage display system and identified a domain inherent in the retinoblastoma protein (pRB). The interaction between pRB and HIF-1alpha was confirmed by in vitro experiments and in transfected cells. Thereby, an HIF-1alpha domain spanning amino acids 530-694 was mapped to be required for pRB binding. Overexpression of pRB provoked transcriptional activation of HIF-1alpha under normoxia. Furthermore, the domain of pRB identified to bind HIF-1alpha in vitro is sufficient to cause HIF-1alpha transcriptional activation with the further notion that phosphorylation deficient pRB shows stronger HIF-1alpha transactivation. Using ChIP analysis, we show that HIF-1alpha responsive elements (HREs) are precipitated using alpha-pRB antibodies. Additionally, a functional interaction between pRB and HIF-1alpha is confirmed by showing that HIF-1alpha reverses the transcription repressor function of pRB.
Budde
Andreja
A
Department of Medicine IV-Experimental Division, Faculty of Medicine, University of Erlangen-Nürnberg, 91054 Erlangen, Germany.
Schneiderhan-Marra
Nicole
N
Petersen
Gabriele
G
Brüne
Bernhard
B
D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000502:physiology; D004268:DNA-Binding Proteins / Q000502:physiology; D050684:E2F Transcription Factors; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008969:Molecular Sequence Data; D020218:Response Elements / Q000502:physiology; D016160:Retinoblastoma Protein / Q000737:chemistry / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology*; D015533:Transcriptional Activation
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D016160:Retinoblastoma Protein; D014157:Transcription Factors