Self-assembly and DNA binding of the blocking factor in X chromosome inactivation

X chromosome inactivation (XCI) is the phenomenon occurring in female mammals whereby dosage compensation of X-linked genes is obtained by transcriptional silencing of one of their two X chromosomes, randomly chosen during early embryo development. The earliest steps of random X-inactivation, involving counting of the X chromosomes and choice of the active and inactive X, are still not understood. To explain "counting and choice," the longstanding hypothesis is that a molecular complex, a "blocking factor" (BF), exists. The BF is present in a single copy and can randomly bind to just one X per cell which is protected from inactivation, as the second X is inactivated by default. In such a picture, the missing crucial step is to explain how the molecular complex is self-assembled, why only one is formed, and how it binds only one X. We answer these questions within the framework of a schematic Statistical Physics model, investigated by Monte Carlo computer simulations. We show that a single complex is assembled as a result of a thermodynamic process relying on a phase transition occurring in the system which spontaneously breaks the symmetry between the X’s. We discuss, then, the BF interaction with X chromosomes. The thermodynamics of the mechanism that directs the two chromosomes to opposite fates could be, thus, clarified. The insights on the selfassembling and X binding properties of the BF are used to derive a quantitative scenario of biological implications describing current experimental evidences on "counting and choice.

Mio padre lavora, mia madre sparecchia

This research is part of the studies on mental representations of children, with the aim of studying their views about the working world of adults, and to determine whether and how these representations change in the transition from kindergarten to primary school.La presente ricerca si inserisce nel filone degli studi sulle rappresentazioni mentali dei bambini, con la finalit? di studiare la loro visione circa il mondo del lavoro degli adulti, e di verificare se e in che modo tali rappresentazioni cambiano nel passaggio dalla scuola dell?infanzia alla scuola primaria

La mobilit? autonoma dei bambini in Italia

The work performed has enabled data to be obtained on Italian children\u27s current level of independent mobility. The data reveal that children\u27s independent mobility rises with age with a significant increase at the time of the transfer from primary to secondary school (11 years old). In addition, it emerges that children and young people tend to overestimate their independence whilst parents tend to underestimate it.Il lavoro svolto ha consentito di acquisire dati sull\u27attuale livello di autonomia dei bambini italiani. Dai dati emerge che la mobilit? autonoma dei bambini aumenta con l\u27et? con un significativo incremento in corrispondenza del passaggio dalla scuola primaria alla secondaria (11 anni). Inoltre emerge che bambini e ragazzi tendono a sovrastimare la loro autonomia mentre i genitori tendono a sottostimarla

Identification of a Consolidation Phase in Immunological Memory

Long lasting antibody responses and immunological memory are the desired outcomes of vaccination. In general, multiple vaccine doses result in enhanced immune responses, a notable exception being booster-induced hyporesponsiveness, which has been observed with polysaccharide and glycoconjugate vaccines. In this study, we analyzed the effect of early booster doses of multimeric protein vaccine (1-11)E2 on recall memory to B epitope 1-11 of β-amyloid. Mice immunized with a single dose of (1-11)E2 stochastically display, when immunized with a recall dose 9 months later, either memory, i.e., an enhanced response to epitope 1-11, or hyporesponsiveness, i.e., a reduced response. Memory is the most common outcome, achieved by 80% of mice. We observed that a booster dose of vaccine (1-11)E2 at day 15 significantly reduced the ratio between the magnitude of the secondary and primary response, causing an increase of hyporesponsive mice. This booster-dependent disruption of recall memory only occurred in a limited time window: a booster dose at day 21 had no significant effect on the ratio between the secondary and primary response magnitude. Thus, this study identifies a consolidation phase in immunological memory, that is a time window during which the formation of memory is vulnerable, and a disrupting stimulus reduces the probability that memory is achieved

Thrombosis in Autoimmune Diseases: A Role for Immunosuppressive Treatments?

Autoimmune diseases are not infrequently associated with arterial or venous thrombotic events. Chronic inflammation and immune system impairment are considered the main pathogenetic mechanisms. Some of the drugs used in the treatment of such diseases have been associated with an increased risk of thrombosis. On the contrary, their anti-inflammatory and immune modulator activity could correct some mechanisms leading to thrombosis. In this review, recent evidence available on this topic is examined. There is a lack of adequate studies, but available evidence suggests that glucocorticoids and high-dose immunoglobulins are associated with an increased incidence of venous thromboembolism. Although available data do not allow drawing definite conclusions and more data are needed from future studies and registries, physicians should be aware of these associations

Thermodynamic pathways to genome spatial organization in the cell nucleus

The architecture of the eukaryotic genome is characterized by a high degree of spatial organization. Chromosomes occupy preferred territories correlated to their state of activity and, yet, displace their genes to interact with remote sites in complex patterns requiring the orchestration of a huge number of DNA loci and molecular regulators. Far from random, this organization serves crucial functional purposes, but its governing principles remain elusive. By computer simulations of a Statistical Mechanics model, we show how architectural patterns spontaneously arise from the physical interaction between soluble binding molecules and chromosomes via collective thermodynamics mechanisms. Chromosomes colocalize, loops and territories form and find their relative positions as stable hermodynamic states. These are selected by “thermodynamic switches” which are regulated by concentrations/affinity of soluble mediators and by number/location of their attachment sites along chromosomes. Our “thermodynamic switch model” of nuclear architecture, thus, explains on quantitative grounds how well known cell strategies of upregulation of DNA binding proteins or modification of chromatin structure can dynamically shape the organization of the nucleus

Evaluation of Radon Exposure Risk and Lung Cancer Incidence/Mortality in South-Eastern Italy

Introduction: Radon and its decay products may cause substantial health damage after long-term exposure. The aim of the study was to perform a spatial analysis of radon concentration in the Salento peninsula, province of Lecce (South-eastern Italy) in order to better characterize possible risk for human health, with specific focus on lung cancer.Methods: Based on previous radon monitoring campaigns carried out in 2006 on behalf of the Local Health Authority (ASL Lecce) involving 419 schools and through the application of kriging estimation method, a radon risk map was obtained for the province of Lecce, in order to determine if areas with higher radon concentrations were overlapping with those characterized by the highest pulmonary cancer incidence and mortality rates.Results: According to our data, areas at higher radon concentrations seem to overlap with those characterized by the highest pulmonary cancer mortality and incidence rates, thus indicating that human exposure to radon could possibly enhance other individual or environmental pro-carcinogenic risk factors (i.e. cigarette smoking, air pollution and other exposures).Conclusions: The radon risk should be further assessed in the evaluation of the causes resulting in higher mortality and incidence rates for pulmonary cancer in Salento area vs Italian average national data. For these reasons, ASL Lecce in cooperation with ARPA Puglia and CNR-IFC has included the monitoring of individual indoor radon concentrations in the protocol of PROTOS case-control Study, aimed at investigating the role of different personal and environmental risk factors for lung cancer in Salento

A Feasible Methodological Approach to Estimate the Burden of Autism Spectrum Disorder: Results from the EPI-ASD Study in the Province of Lecce (Southern Italy)

Diagnoses of Autism Spectrum Disorder (ASD) have rapidly increased globally. However, the lack of comprehensive epidemiological surveys and surveillance systems, able to provide official data at a national or European level is one of the main issues in the monitoring of this condition. The present study aimed to estimate the prevalence of ASD in children and adolescents aged 3-18 years old living in the province of Lecce (Southern Italy) through official data provided by the Local Health Authority of Lecce (ASL/LE) up to 31 October 2020, and compare it with school-based data concerning the number of students needing support for ASD. Based on data provided by the ASL/LE, in 2020 there were 509 cases of ASD among children and adolescents aged 3-18 years old, corresponding to a prevalence of 0.46%. A total of 408 (80.2%) were boys and 101 (19.8%) were girls. In relation to their age, 155 ASD cases (0.90%) were diagnosed in the 3-5 age group, while 222 (0.55%) in the 6-11 age group and 132 (0.25%) in the 12-18 age group. Prevalence of ASD assessed by school-based dataset was underestimated in the 3-5 age group, while the 6-11 and 12-18 age groups were consistent with the official data provided by the ASL/LE