RESUMEN
Parchment is an ancient writing support formed from dehaired animal skins. Its manufacture comprises a series of liming and scraping steps before being stretched and dried under tension. Historical parchment represents a valuable source of cultural heritage which, until now, has limited investigations to noninvasive analyses to infer ink composition, degradation, or physical changes over time. We highlight the prospect of the molecular and isotope compositions of animal lipids from parchment as an untapped record of its production and the animal's diet and environment. We report a minimally invasive, total lipid extraction aided by a vacuum for historical parchments. The quantitative and qualitative compositions of lipid extracts obtained using this method are compared with those obtained using invasive sampling for nine sacrificial membranes dated 1765-1825 CE. This extraction method is then applied to membranes from the Chancery Parliament Rolls (1814-1820 CE) held by The National Archives, UK to obtain lipids and derive taxonomic and dietary information using their stable carbon isotope compositions. This novel vacuum-aided extraction allows, for the first time, animal lipids to be obtained from parchment minimally invasively, paving the way for dietary and paleoclimate studies using this well-dated and common material.
RESUMEN
The PAF complex (PAFC) coordinates transcription elongation and mRNA processing and its CDC73/parafibromin subunit functions as a tumour suppressor. The NF2/Merlin tumour suppressor functions both at the cell cortex and nucleus and is a key mediator of contact inhibition but the molecular mechanisms remain unclear. In this study we have used affinity proteomics to identify novel Merlin interacting proteins and show that Merlin forms a complex with multiple proteins involved in RNA processing including the PAFC and the CHD1 chromatin remodeller. Tumour-derived inactivating mutations in both Merlin and the CDC73 PAFC subunit mutually disrupt their interaction and growth suppression by Merlin requires CDC73. Merlin interacts with the PAFC in a cell density-dependent manner and we identify a role for FAT cadherins in regulating the Merlin-PAFC interaction. Our results suggest that in addition to its function within the Hippo pathway, Merlin is part of a tumour suppressor network regulated by cell-cell adhesion which coordinates post-initiation steps of the transcription cycle of genes mediating contact inhibition.
Asunto(s)
Adhesión Celular/genética , ADN Helicasas/genética , Proteínas de Unión al ADN/genética , Neoplasias/genética , Neurofibromina 2/genética , Proteínas Supresoras de Tumor/genética , Proliferación Celular/genética , Cromatina/genética , Ensamble y Desensamble de Cromatina/genética , Inhibición de Contacto/genética , Regulación de la Expresión Génica/genética , Células HEK293 , Humanos , Neoplasias/patología , Unión Proteica/genética , Mapas de Interacción de Proteínas/genética , Transducción de Señal/genéticaRESUMEN
SHOC2 is mutated in Noonan syndrome and plays a key role in the activation of the ERK-MAPK pathway, which is upregulated in the majority of human cancers. SHOC2 functions as a PP1-regulatory protein and as an effector of MRAS. Here we show that SHOC2 and MRAS form a complex with SCRIB, a polarity protein with tumor suppressor properties. SCRIB functions as a PP1-regulatory protein and antagonizes SHOC2-mediated RAF dephosphorylation through a mechanism involving competition for PP1 molecules within the same macromolecular complex. SHOC2 function is selectively required for the malignant properties of tumor cells with mutant RAS, and both MRAS and SHOC2 play a key role in polarized migration. We propose that MRAS, through its ability to recruit a complex with paradoxical components, coordinates ERK pathway spatiotemporal dynamics with polarity and that this complex plays a key role during tumorigenic growth.
Asunto(s)
Péptidos y Proteínas de Señalización Intracelular/genética , Sistema de Señalización de MAP Quinasas/genética , Proteínas de la Membrana/genética , Proteínas Supresoras de Tumor/genética , Proteínas ras/genética , Carcinogénesis/genética , Carcinogénesis/metabolismo , Línea Celular , Movimiento Celular/genética , Células HEK293 , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Sustancias Macromoleculares/metabolismo , Proteínas de la Membrana/metabolismo , Fosforilación , Receptores de Neuropéptido Y/genética , Receptores de Neuropéptido Y/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Quinasas raf/genética , Quinasas raf/metabolismo , Proteínas ras/metabolismoRESUMEN
Bilaterality of breast cancer is an indicator of constitutional cancer susceptibility; however, the molecular causes underlying this predisposition in the majority of cases is not known. We hypothesize that epigenetic misregulation of cancer-related genes could partially account for this predisposition. We have performed methylation microarray analysis of peripheral blood DNA from 14 women with bilateral breast cancer compared with 14 unaffected matched controls throughout 17 candidate breast cancer susceptibility genes including BRCA1, BRCA2, CHEK2, ATM, ESR1, SFN, CDKN2A, TP53, GSTP1, CDH1, CDH13, HIC1, PGR, SFRP1, MLH1, RARB and HSD17B4. We show that the majority of methylation variability is associated with intragenic repetitive elements. Detailed validation of the tiled region around ATM was performed by bisulphite modification and pyrosequencing of the same samples and in a second set of peripheral blood DNA from 190 bilateral breast cancer patients compared with 190 controls. We show significant hypermethylation of one intragenic repetitive element in breast cancer cases compared with controls (P = 0.0017), with the highest quartile of methylation associated with a 3-fold increased risk of breast cancer (OR 3.20, 95% CI 1.78-5.86, P = 0.000083). Increased methylation of this locus is associated with lower steady-state ATM mRNA level and correlates with age of cancer patients but not controls, suggesting a combined age-phenotype-related association. This research demonstrates the potential for gene-body epigenetic misregulation of ATM and other cancer-related genes in peripheral blood DNA that may be useful as a novel marker to estimate breast cancer risk. ACCESSION NUMBERS: The microarray data and associated .BED and .WIG files can be accessed through Gene Expression Omnibus accession number: GSE14603.