PBRM1-deficient PBAF complexes target de novo genomic loci to activate pro-survival genes in clear cell renal cell carcinoma (BRG1 dataset)

ABSTRACT: PBRM1 is lost in 40% of clear cell renal cell carcinomas (ccRCC) and the combined loss of VHL and PBRM1 drives ccRCC tumorigenesis. PBRM1 is an accessory subunit of the PBAF subclass of the SWI/SNF chromatin remodeler and despite its well-established role as a tumor suppressor, we have limited understanding of how PBRM1 regulates the chromatin. Now we report that PBRM1 binds to promoter-proxy regions with footprints at +1 to + 3 nucleosomes. PBRM1-deficient PBAF complexes lose BRD7 but retain ARID2, while tethered to SMARCA4. The lack of PBRM1-BRD7 module compromises the targeting specificity of the PBAF complexes, causes their genomic redistribution and impairs the repressive ability of PBAF complexes. Subsequently, PBRM1-deficient PBAF complexes prime the chromatin at de novo sites for transcriptional activation of pro-survival genes involved in hypoxia and cholesterol synthesis. Therefore, PBRM1 safeguards the chromatin by repressing aberrant liberation of pro-survival genes by residual PBRM1-deficient SWI/SNF complexes.

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Xiaosai Yao 

PROVIDER: PXD020553 | JPOST Repository | Sat Jul 24 00:00:00 BST 2021

REPOSITORIES: jPOST