Dataset Information

Hypoxia-responsive interaction between Cyclin T1, BHLHE40, and Tim8-Tim13 regulates RNA Polymerase II

ABSTRACT: P-TEFb regulates the pause release checkpoint on transcription by RNA Polymerase II. We sought hypoxia-specific interactions that could direct PTEF-b activity to hypoxia-responsive genes. Using a biochemical purification approach, we discovered a hypoxia-specific, chromatin-associated interaction between the P-TEFb subunit Cyclin T1 (CCNT1), the mitochondrial chaperone Tim8-Tim13 complexes, and the hypoxia-inducible, DNA-binding transcription factor BHLHE40. This interaction is conserved across diverse cell line models. Tim8-Tim13 complex disruption and BHLHE40 silencing both impair the transcriptional response to acute hypoxia by RNAPII in DLD-1 cells. HIF is not involved in the CCNT1/BHLHE40/Tim8-Tim13 interaction, and BHLHE40 expression is not entirely HIF-dependent: neither genetic HIF-1β knockout nor pharmacological inhibition of HIF-2α using belzutifan eliminates BHLHE40. Finally, BHLHE40 depletion compromises the proliferation of 786-O clear cell renal carcinoma cells, which constitutively express HIF-2α and hypoxia-responsive genes. Together, these findings reveal a HIF-independent regulatory axis in which Tim8a-Tim13 complexes and BHLHE40 that modulate PTEF-b activity in the transcriptional response to hypoxia.

ORGANISM(S): Homo sapiens

PROVIDER: GSE293152 | GEO | 2026/04/10

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:To investigate the detailed molecular mechanisms for the regulatory role of HIF-2α in experimental colitis, microarray gene expression analysis was performed on colon RNA isolated from 6- to 8-week-old Hif-2αF/F, Hif-2αlΔIE mice treated with 3%DSS for 3 days. Background & Aims: Hypoxic inflammation is characterized by decreased oxygen tension in inflammatory foci, and is a notable feature in inflammatory bowel disease (IBD). Hypoxic response is mediated by transcription factors hypoxia-inducible factor (HIF)-1α and HIF-2α, both of which are highly induced in IBD. HIF-1α is a protective factor that limits intestinal barrier dysfunction during inflammation. However, the role of HIF-2α has not been assessed in hypoxic inflammation and IBD. Methods: A hypoxia reporter mouse model was used to test the presence of hypoxia and HIF-2α in dextran sulfate sodium (DSS) and Citrobacter rodentium (C.rod)-induced colitis. The role of HIF-2α in these mouse models of colitis was further assessed in mice with an intestinal epithelium-specific gain- and loss-of-function of HIF-2α. Results: Induction of hypoxia and HIF-2α was confirmed in both murine experimental colitis models and human IBD samples. Disruption of HIF-2α attenuated colonic inflammation whereas stabilization of HIF-2α potentiated inflammation in mouse models of colitis. Interestingly, intestine specific overexpression of HIF-2α but not HIF-1α leads to spontaneous colitis and premature death in mice. Further mechanistic analysis showed that HIF-2α is a driver for pro-inflammatory response and is critical regulator of intestinal epithelial-derived tumor necrosis factor (TNF)-α. Blocking TNF-α completely ameliorated HIF-2α potentiated intestinal inflammation. Conclusions: These data demonstrate that HIF-2α is a critical transcription factor essential in intestinal epithelium elicited inflammatory response. Global gene expression profiling in colon RNAs isolated from 7-week-old Hif-2αF/F (n=6, Shah 007) and Hif-2αΔIE (n=5, Shah 008).

Dataset Information

Hypoxia-responsive interaction between Cyclin T1, BHLHE40, and Tim8-Tim13 regulates RNA Polymerase II

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets