RESUMEN
Alternative polyadenylation (APA) contributes to transcriptome complexity by generating mRNA isoforms with varying 3' UTR lengths. APA leading to 3' UTR shortening (3' US) is a common feature of most cancer cells; however, the molecular mechanisms are not understood. Here, we describe a widespread mechanism promoting 3' US in cancer through ubiquitination of the mRNA 3' end processing complex protein, PCF11, by the cancer-specific MAGE-A11-HUWE1 ubiquitin ligase. MAGE-A11 is normally expressed only in the male germline but is frequently re-activated in cancers. MAGE-A11 is necessary for cancer cell viability and is sufficient to drive tumorigenesis. Screening for targets of MAGE-A11 revealed that it ubiquitinates PCF11, resulting in loss of CFIm25 from the mRNA 3' end processing complex. This leads to APA of many transcripts affecting core oncogenic and tumor suppressors, including cyclin D2 and PTEN. These findings provide insights into the molecular mechanisms driving APA in cancer and suggest therapeutic strategies.
Asunto(s)
Regiones no Traducidas 3'/genética , Antígenos de Neoplasias/metabolismo , Neoplasias Pulmonares/patología , Proteínas de Neoplasias/metabolismo , Neoplasias Ováricas/patología , ARN Mensajero/metabolismo , Ubiquitina/metabolismo , Factores de Escisión y Poliadenilación de ARNm/metabolismo , Animales , Antígenos de Neoplasias/genética , Apoptosis , Biomarcadores de Tumor , Carcinogénesis , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Proliferación Celular , Factor de Especificidad de Desdoblamiento y Poliadenilación/genética , Factor de Especificidad de Desdoblamiento y Poliadenilación/metabolismo , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Proteínas de Neoplasias/genética , Neoplasias Ováricas/genética , Neoplasias Ováricas/metabolismo , Poliadenilación , Empalme del ARN , ARN Mensajero/genética , Células Tumorales Cultivadas , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación , Ensayos Antitumor por Modelo de Xenoinjerto , Factores de Escisión y Poliadenilación de ARNm/genéticaRESUMEN
Melanoma antigen L2 (MAGEL2 or MAGE-L2) is a member of the MAGE family of ubiquitin ligase regulators. It is maternally imprinted and often paternally deleted or mutated in the related neurodevelopmental syndromes, Prader-Willi Syndrome (PWS) and Schaaf-Yang Syndrome (SHFYNG). MAGEL2 is highly expressed in the hypothalamus and plays an important role in a fundamental cellular process that recycles membrane proteins from endosomes through the retromer sorting pathway. MAGEL2 is part of a multi-subunit protein complex consisting of MAGEL2, the TRIM27 E3 ubiquitin ligase, and the USP7 deubiquitinating enzyme. The MAGEL2-USP7-TRIM27 (or MUST) complex facilitates the retromer recycling pathway through ubiquitination and activation of the WASH actin nucleation promoting factor. This review provides an overview of the MAGE protein family of ubiquitin ligases regulators and details the molecular and cellular role of MAGEL2 in ubiquitination, actin regulation and endosomal sorting processes, as well as MAGEL2 implications in PWS and SHFYNG disorders. The physiological functions of MAGEL2, elucidated through the study of Magel2 knockout mouse models, are also discussed.
Asunto(s)
Endosomas/metabolismo , Síndrome de Prader-Willi/metabolismo , Síndrome de Prader-Willi/patología , Proteínas/metabolismo , Humanos , Transporte de Proteínas , UbiquitinaciónRESUMEN
PURPOSE: The aim of our study was to determine whether there are any differences in the cumulus cell gene expression profile of mature oocytes derived from modified natural IVF and controlled ovarian hyperstimulation cycles and if these changes could help us understand why modified natural IVF has lower success rates. METHODS: Cumulus cells surrounding mature oocytes that developed to morulae or blastocysts on day 5 after oocyte retrieval were submitted to microarray analysis. The obtained data were then validated using quantitative real-time PCR. RESULTS: There were 66 differentially expressed genes between cumulus cells of modified natural IVF and controlled ovarian hyperstimulation cycles. Gene ontology analysis revealed the oxidation-reduction process, glutathione metabolic process, xenobiotic metabolic process and gene expression were significantly enriched biological processes in MNIVF cycles. Among differentially expressed genes we observed a large group of small nucleolar RNA's whose role in folliculogenesis has not yet been established. CONCLUSION: The increased expression of genes involved in the oxidation-reduction process probably points to hypoxic conditions in modified natural IVF cycles. This finding opens up new perspectives for the establishment of the potential role that oxidation-reduction processes have in determining success rates of modified natural IVF.
Asunto(s)
Células del Cúmulo/metabolismo , Fertilización In Vitro , Fertilización/genética , Expresión Génica , Adulto , Femenino , Perfilación de la Expresión Génica , Humanos , Análisis de Secuencia por Matrices de Oligonucleótidos , Recuperación del Oocito , Inducción de la Ovulación , Embarazo , Resultado del Embarazo/genética , Índice de Embarazo , TranscriptomaRESUMEN
Prader-Willi syndrome (PWS) is a developmental disorder caused by loss of maternally imprinted genes on 15q11-q13, including melanoma antigen gene family member L2 (MAGEL2). The clinical phenotypes of PWS suggest impaired hypothalamic neuroendocrine function; however, the exact cellular defects are unknown. Here, we report deficits in secretory granule (SG) abundance and bioactive neuropeptide production upon loss of MAGEL2 in humans and mice. Unbiased proteomic analysis of Magel2pΔ/m+ mice revealed a reduction in components of SG in the hypothalamus that was confirmed in 2 PWS patient-derived neuronal cell models. Mechanistically, we show that proper endosomal trafficking by the MAGEL2-regulated WASH complex is required to prevent aberrant lysosomal degradation of SG proteins and reduction of mature SG abundance. Importantly, loss of MAGEL2 in mice, NGN2-induced neurons, and human patients led to reduced neuropeptide production. Thus, MAGEL2 plays an important role in hypothalamic neuroendocrine function, and cellular defects in this pathway may contribute to PWS disease etiology. Moreover, these findings suggest unanticipated approaches for therapeutic intervention.
Asunto(s)
Antígenos de Neoplasias/fisiología , Hipotálamo/patología , Neuronas/patología , Neuropéptidos/metabolismo , Síndrome de Prader-Willi/fisiopatología , Proteínas/metabolismo , Proteínas/fisiología , Vesículas Secretoras/patología , Animales , Femenino , Humanos , Hipotálamo/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neuronas/metabolismo , Fenotipo , Transporte de Proteínas , Proteínas/genética , Proteoma/análisis , Proteoma/metabolismo , Vesículas Secretoras/metabolismoRESUMEN
Novel cholesterol biosynthesis inhibitors, a group of pyridylethanol(phenylethyl)amine derivatives, were synthesized. Sterol profiling assay in the human hepatoma HepG2 cells revealed that compounds target human lanosterol 14alpha-demethylase (CYP51). Structure-activity relationship study of the binding with the overexpressed human CYP51 indicates that the pyridine binds within the heme binding pocket in an analogy with the azoles.