RESUMO
The ARID1A subunit of SWI/SNF chromatin remodeling complexes is a potent tumor suppressor. Here, a degron is applied to detect rapid loss of chromatin accessibility at thousands of loci where ARID1A acts to generate accessible minidomains of nucleosomes. Loss of ARID1A also results in the redistribution of the coactivator EP300. Co-incident EP300 dissociation and lost chromatin accessibility at enhancer elements are highly enriched adjacent to rapidly downregulated genes. In contrast, sites of gained EP300 occupancy are linked to genes that are transcriptionally upregulated. These chromatin changes are associated with a small number of genes that are differentially expressed in the first hours following loss of ARID1A. Indirect or adaptive changes dominate the transcriptome following growth for days after loss of ARID1A and result in strong engagement with cancer pathways. The identification of this hierarchy suggests sites for intervention in ARID1A-driven diseases.
Assuntos
Proteínas de Ligação a DNA/deficiência , Células-Tronco Embrionárias Murinas/metabolismo , Nucleossomos/metabolismo , Lesões Pré-Cancerosas/metabolismo , Fatores de Transcrição/deficiência , Transcrição Gênica , Ativação Transcricional , Animais , Sítios de Ligação , Linhagem Celular , Montagem e Desmontagem da Cromatina , Proteínas de Ligação a DNA/genética , Proteína p300 Associada a E1A/genética , Proteína p300 Associada a E1A/metabolismo , Masculino , Camundongos , Camundongos da Linhagem 129 , Nucleossomos/genética , Lesões Pré-Cancerosas/genética , Proteólise , Fatores de Tempo , Fatores de Transcrição/genéticaRESUMO
We describe a simple method for the direct modification of nucleobases in cyclic purine dinucleotides, important signalling molecules in both prokaryotes and eukaryotes. The method tolerates all members of the cyclic dinucleotide family and could be used to modulate their function or introduce useful side-chains such as fluorophores and photo-crosslinking groups.
