Transcription is required for establishment of germline methylation marks at imprinted genes

Genomic imprinting requires the differential marking by DNA methylation of genes in male and female gametes. In the female germline, acquisition of methylation imprint marks depends upon the de novo methyltransferase Dnmt3a and its cofactor Dnmt3L, but the reasons why specific sequences are targets for Dnmt3a and Dnmt3L are still poorly understood. Here, we investigate the role of transcription in establishing maternal germline methylation marks. We show that at the Gnas locus, truncating transcripts from the furthest upstream Nesp promoter disrupts oocyte-derived methylation of the differentially methylated regions (DMRs). Transcription through DMRs in oocytes is not restricted to this locus but occurs across the prospective DMRs at many other maternally marked imprinted domains, suggesting a common requirement for transcription events. The transcripts implicated here in gametic methylation are protein-coding, in contrast to the noncoding antisense transcripts involved in the monoallelic silencing of imprinted genes in somatic tissues, although they often initiate from alternative promoters in oocytes. We propose that transcription is a third essential component of the de novo methylation system, which includes optimal CpG spacing and histone modifications, and may be required to create or maintain open chromatin domains to allow the methylation complex access to its preferred targets

La desescalada de las medidas de mitigación contra el COVID-19 en España (mayo–junio 2020)

[EN] Introduction: The state of alarm was declared in Spain due to the COVID-19 epidemic on March 14, 2020, and established population confinement measures. The objective is to describe the process of lifting these mitigation measures. Methods: The Plan for the Transition to a New Normality, approved on April 28, contained four sequential phases with progressive increase in socio-economic activities and population mobility. In parallel, a new strategy for early diagnosis, surveillance and control was implemented. A bilateral decision mechanism was established between the Spanish Government and the autonomous communities (AC), guided by a set of qualitative and quantitative indicators capturing the epidemiological situation and core capacities. The territorial units were established ad-hoc and could be from Basic Health Zones to entire AC. Results: The process run from May 4 to June 21, 2020. AC implemented plans for reinforcement of core capacities. Incidence decreased from a median (50% of territories) of 7.4 per 100,000 in 7 days at the beginning to 2.5 at the end. Median PCR testing increased from 53% to 89% of suspected cases and PCR total capacity from 4.5 to 9.8 per 1000 inhabitants weekly; positivity rate decreased from 3.5% to 1.8%. Median proportion of cases with traced contacts increased from 82% to 100%. Conclusion: Systematic data collection, analysis, and interterritorial dialogue allowed adequate process control. The epidemiological situation improved but, mostly, the process entailed a great reinforcement of core response capacities nation-wide, under common criteria. Maintaining and further reinforcing capacities remained crucial for responding to future waves. [ES] Introducción: El 14 de marzo de 2020 España declaró el estado de alarma por la pandemia por COVID-19 incluyendo medidas de confinamiento. El objetivo es describir el proceso de desescalada de estas medidas. Métodos: Un plan de transición hacia una nueva normalidad, del 28 de abril, incluía 4 fases secuenciales incrementando progresivamente las actividades socioeconómicas y la movilidad. Concomitantemente, se implementó una nueva estrategia de diagnóstico precoz, vigilancia y control. Se estableció un mecanismo de decisión bilateral entre Gobierno central y comunidades autónomas (CCAA), guiado por un panel de indicadores cualitativos y cuantitativos de la situación epidemiológica y las capacidades básicas. Las unidades territoriales evaluadas comprendían desde zonas básicas de salud hasta CCAA. Resultados: El proceso se extendió del 4 de mayo al 21 de junio y se asoció a planes de refuerzo de las capacidades en las CCAA. La incidencia disminuyó de una mediana inicial de 7,4 por 100.000 en 7 días a 2,5 al final del proceso. La mediana de pruebas PCR aumentó del 53% al 89% de los casos sospechosos, y la capacidad total de 4,5 a 9,8 pruebas semanales por 1.000 habitantes; la positividad disminuyó del 3,5% al 1,8%. La mediana de casos con contactos trazados aumentó del 82% al 100%. Conclusión: La recogida y análisis sistemático de información y el diálogo interterritorial logaron un adecuado control del proceso. La situación epidemiológica mejoró, pero sobre todo, se aumentaron las capacidades, en todo el país y con criterios comunes, cuyo mantenimiento y refuerzo fue clave en olas sucesivas.S