RESUMO
Genes encoding subunits of SWI/SNF (BAF) chromatin remodeling complexes are mutated in nearly 25% of cancers. To gain insight into the mechanisms by which SWI/SNF mutations drive cancer, we contributed ten rhabdoid tumor (RT) cell lines mutant for SWI/SNF subunit SMARCB1 to a genome-scale CRISPR-Cas9 depletion screen performed across 896 cell lines. We identify PHF6 as specifically essential for RT cell survival and demonstrate that dependency on Phf6 extends to Smarcb1-deficient cancers in vivo. As mutations in either SWI/SNF or PHF6 can cause the neurodevelopmental disorder Coffin-Siris syndrome, our findings of a dependency suggest a previously unrecognized functional link. We demonstrate that PHF6 co-localizes with SWI/SNF complexes at promoters, where it is essential for maintenance of an active chromatin state. We show that in the absence of SMARCB1, PHF6 loss disrupts the recruitment and stability of residual SWI/SNF complex members, collectively resulting in the loss of active chromatin at promoters and stalling of RNA Polymerase II progression. Our work establishes a mechanistic basis for the shared syndromic features of SWI/SNF and PHF6 mutations in CSS and the basis for selective dependency on PHF6 in SMARCB1-mutant cancers.
Assuntos
Micrognatismo , Regiões Promotoras Genéticas , Proteínas Repressoras , Tumor Rabdoide , Proteína SMARCB1 , Fatores de Transcrição , Animais , Humanos , Masculino , Camundongos , Anormalidades Múltiplas , Linhagem Celular Tumoral , Cromatina/metabolismo , Montagem e Desmontagem da Cromatina , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Cromossômicas não Histona/genética , Sistemas CRISPR-Cas , Face/anormalidades , Deformidades Congênitas do Pé/genética , Deformidades Congênitas do Pé/metabolismo , Deformidades Congênitas da Mão , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Micrognatismo/genética , Micrognatismo/metabolismo , Mutação , Pescoço/anormalidades , Regiões Promotoras Genéticas/genética , Proteínas Repressoras/metabolismo , Proteínas Repressoras/genética , Tumor Rabdoide/genética , Tumor Rabdoide/metabolismo , Tumor Rabdoide/patologia , Proteína SMARCB1/metabolismo , Proteína SMARCB1/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Transcrição GênicaRESUMO
Background: Since the coronavirus (COVID-19) pandemic began, several studies were published on the possible prevention and treatment of the disease caused by severe acute respiratory syndrome coronavirus (SARSCoV-2), and its complications. However, one aspect that was overlooked is the impact on the mental health of the caregivers of COVID-19 patients. The current study endeavors to investigate sleep quality disturbances in the caregivers of COVID-19 patients in different countries. Material and Methods: This cross-sectional multi-center study was performed between August 1, 2021, and August 30, 2022, across 11 countries. A total of 2411 responses meeting the inclusion criteria (being a family member or caregiver involved in patient care) were collected. The sleep quality was assessed using the self-reported Pittsburgh Sleep Quality Index (PSQI) 12. Total scores ranged from 0 to 21. A ≥5 indicated poor sleep quality with 89.6% sensitivity and 86.5% specificity. Results: A total of 2411 responses meeting the inclusion criteria showed that mean PSQI scores (P = 0.3604) were higher in caregivers of hospitalized patients than in patients isolated at home. Approximately 62.4% of caregivers reported sleep quality problems while caring for their patients. Conclusion: The results showed that the majority of caregivers of patients with COVID-19 reported disturbances in sleep quality and impaired sleep was more common among caregivers of hospitalized patients, perhaps because hospitalization is associated with a more severe course of the disease. There is a pressing need to take measures to improve the mental health of these caregivers. There should be treatment programs set up to reverse sleep disturbances in this population sufficiently.
RESUMO
Cells employ transcription-coupled repair (TCR) to eliminate transcription-blocking DNA lesions. DNA damage-induced binding of the TCR-specific repair factor CSB to RNA polymerase II (RNAPII) triggers RNAPII ubiquitylation of a single lysine (K1268) by the CRL4CSA ubiquitin ligase. How CRL4CSA is specifically directed towards K1268 is unknown. Here, we identify ELOF1 as the missing link that facilitates RNAPII ubiquitylation, a key signal for the assembly of downstream repair factors. This function requires its constitutive interaction with RNAPII close to K1268, revealing ELOF1 as a specificity factor that binds and positions CRL4CSA for optimal RNAPII ubiquitylation. Drug-genetic interaction screening also revealed a CSB-independent pathway in which ELOF1 prevents R-loops in active genes and protects cells against DNA replication stress. Our study offers key insights into the molecular mechanisms of TCR and provides a genetic framework of the interplay between transcriptional stress responses and DNA replication.