Nucleosomes in gene regulation: theoretical approaches

This work reviews current theoretical approaches of biophysics and bioinformatics for the description of nucleosome arrangements in chromatin and transcription factor binding to nucleosomal organized DNA. The role of nucleosomes in gene regulation is discussed from molecular-mechanistic and biological point of view. In addition to classical problems of this field, actual questions of epigenetic regulation are discussed. The authors selected for discussion what seem to be the most interesting concepts and hypotheses. Mathematical approaches are described in a simplified language to attract attention to the most important directions of this field

Effect of flanking sequences on the accuracy of the recognition of transcription factor binding sites

The development of in vitro methods produced new experimental information on protein binding to DNA, which is accumulated in databases and used in studies of mechanisms regulating gene expression and in the development of computer-assisted methods of binding site recognition in pro- and eukaryotic genomes. However, it is still questionable to what extent sequences selected in vitro reflect the actual structures of natural transcription factor (TF) binding sites. The Kullback – Leibler divergence was applied to the comparison of frequency matrices of TF binding sites constructed on samples of artificially selected sequences and natural sites. Core sequences of natural and artificial sites showed high similarity for 80 % of all TFs studied. For 20 % of TFs, binding site sequences selected in vitro had a broader range of permissible significant nucleotides not found in natural sites. The optimum lengths of DNA sequences including natural binding sites, at which they are recognized most accurately, were estimated by the weight matrix method. For approximately 80 % of the TFs studied, the optimum binding site length notably exceeded the lengths of the core sequences, as well as the lengths of in vitro selected sites. The detected features of in vitro selected TF binding sites impose constraints on their use in the development of computer-assisted methods of the recognition of candidate sites in genomic sequences

Status of child population health — the future of the country (part 1)

The article of the team of scientists of pediatricians and organizers of pediatric health care of Ukraine is devoted to the study of the main trends in the health status of children over last 22 years. The results of the analysis of the incidence and prevalence of diseases among Ukrainian child population, infant mortality rates over the past two decades demonstrates that they remain significantly higher than the average European indicators against the background of a progressive decrease in the number of child population at 3,16 million people. The prevalence of childhood diseases in Ukraine over past 22 years has grown by 41 %, the incidence of childhood diseases arose by 36 %. The article considers the ways of solving a number of new social and medico-ecological problems that negatively affect child health

Child health status — the future of the country (part 2)

The article deals with the problems of increasing the incidence and prevalence of childhood diseases during 1994–2016 against the background of a global reduction in the staffing of children’s specialists by 1.7 times, with an extremely inadequate supply of the regions of the South-East, Donetsk and Luhansk regions. All of this has a negative impact on the proper medical care of the child population, including the detection of childhood diseases. The authors substantiate the need to restore the personnel and material-technical potential of the pediatric service, the development of modern diagnostic and treatment technologies, the preservation of immunization and the prevention of disability of common childhood diseases that is an important component of the national health care and safety system of the country as a whole