Insulators in vertebrates: regulatory mechanisms and chromatin structure

Инсуляторы были открыты как геномные элементы, способные прерывать связь между промотором и энхансером (энхансер-блокирующая активность) и ограничивать распространение гетерохроматина (барьерная активность). У дрозофилы существует несколько типов инсуляторов, работающих посредством привлечения различных белков. Все описанные инсуляторы у позвоночных животных работают при участии многофункционального транскрипционного фактора CTCF. Биологические функции инсуляторов позвоночных животных не вполне ясны. Хотя принято считать, что они разграничивают хроматиновые домены, прямых свидетельств этому практически нет. Наиболее показательным является участие инсуляторов в работе центров установления импринтинга (imprinting choice regions). Результаты ряда недавно опубликованных работ свидетельствуют о том, что для установления импринтинга существенным является встраивание инактивированного гена в отдельный топологический домен (петлю). В этом и многих других случаях инсуляторы работают в качестве архитектурных элементов, поддерживающих трехмерную организацию генома. Взаимодействие между парами инсуляторов, в котором наряду с CTCF значительную роль играет когезин, организует геном в различного рода петли. Ключевые слова: хроматиновый домен, барьерный элемент, энхансер-блокирующий элемент, CTCF, импринтинг.Інсулятори було відкрито як геномні елементи, здатні переривати зв’язок між промотором і енхансером (активність, яка блокує функціонування енхансера), та обмежувати поширення гетерохроматину (бар’єрна активність). У дрозофіли існує декілька типів інсуляторів, які працюють із залученням різних білків. Всі описані інсулятори у ссавців працюють за участі багатофункціонального транскрипційного фактора CTCF. Біологічні функції інсуляторів ссавців не до кінця з’ясовані. Хоча багато хто вважає, що вони розмежовують хроматинові домени, прямих свідчень цьому практично немає. Найпоказовішою є участь інсуляторів у роботі центрів встановлення імпринтингу (imprinting choice regions). Результати низки недавно опублікованих робіт свідчать про те, що для встановлення імпринтингу суттєвим є вбудовування інактивованого гена в окремий топологічний домен (петлю). В цьому та в багатьох інших випадках інсулятори працюють як архітектурні елементи, які підтримують тривимірну організацію геному. Взаємодія між парами інсуляторів, у яких поряд з CTCF істотну роль відіграє когезин, організує геном у різного роду петлі. Ключові слова: хроматиновий домен, бар’єрний елемент, енхансер-блокуючий елемент, CTCF, імпринтинг.Insulators were first identified as genomic elements either blocking communication between promoters and enhancers (enhancerblocking activity) or restricting heterochromatin spreading (barrier activity). There are several types of insulators in Drosophila which utilize different proteins. All insulators identified in vertebrates work with the help of the multifunctional transcription factor CTCF. Biological functions of vertebrate insulators are not clear yet. They are supposed to separate chromatin domains albeit there is almost none direct evidence of this fact. The most significant is the participation of insulators in maintenance of centers of imprinting (imprinting choice regions). The results of a number of recently published articles indicate that isolation of a gene by placement of this gene into a separate topological domain (loop) is crucial to establishing imprinting. In this particular case as well as in many other cases insulators serve as architectural elements supporting the three-dimensional structure of genome. Moreover, interaction between pairs of insulators where cohesin plays a pivotal role along with CTCF folds genome into various loops. Keywords: chromatin domain, barrier element, enhancer-blocking element, CTCF, imprinting

Insertion of short hepatitis virus A amino acid sequences into poliovirus antigenic determinants results in viable progeny

AbstractIn an infectious poliovirus cDNA construct, the determinant encoding antigenic epitope N-Agl (in a loop located between two β-strands in polypeptide VP1) was altered by site-directed mutagenesis, to be partially similar with the determinants for presumptive epitopes in polypeptides VP1 or VP3 of hepatitis A virus (HAV). The modified constructs proved to be infectious. However, another construct, in which the same locus encoded a ‘nonsense’ and a relatively hydrophobic amino acid sequence, exhibited no infectivity. These data showed the feasibility of the insertion of foreign sequences in a specific antigenically active locus of the poliovirus icosahedron, and suggest some limitations with respect to the sequences to be ‘transplanted’

The development of portal hypertension and liver failure on the background of long-term intake of vitamin A in a young woman. Case report [Развитие портальной гипертензии и печеночной недостаточности у молодой женщины на фоне длительного приема витамина А. Клиническое наблюдение]

The use of over-the-Counter (OTC) pharmaceuticals is a common phenomenon in today's society. We present a case of liver injury associated with long-term OTC use of vitamin A. The young patient took daily up to 15 capsules of a combined preparation for 2 years containing retinol palmitate 55 mg (100,000 IU) + Alpha-Tocopherol acetate 100 mg, the content of vitamin A in which significantly exceeded the recommended daily dose. Gradually, the patient noted the appearance of arthralgia, skin itching, hyperemia of the palms and feet, exfoliation of the skin on the soles, profuse hair loss, cracks in the corners of the mouth and in the area of the earlobes. Patient's condition worsened with the development of signs of liver cirrhosis in the form of portal hypertension (ascites, splenomegaly) and a decrease in the protein-synthetic function of the organ. Chronic viral hepatitis, autoimmune hepatitis, primary biliary cirrhosis, hemochromatosis, Wilson's disease, alcoholic liver disease were exclude. Liver biopsy showed characteristic signs of hypervitaminosis A without fibrosis. A complete regression of symptoms was observe within 8 months after discontinuation of the drug. A toxicity can lead to serious liver injury and should be considere in the differential diagnosis of chronic liver disease. Vitamin A should only be prescribe for medical reasons, for a limited period of time, and under close medical supervision. © 2022 Consilium Medikum. All rights reserved

Theoretical and empirical approaches to using films as a means to increase communication efficiency.

The theoretical framework of this analytic study is based on studies in the field of film perception. Films are considered as a communicative system that is encrypted in an ordered series of shots, and decoding proceeds during perception. The shots are the elements of a cinematic message that must be “read” by viewer. The objective of this work is to analyze the existing theoretical approaches to using films in psychotherapy and education. An original approach to film therapy that is based on teaching clients to use new communicative sets and psychotherapeutic patterns through watching films is presented. The article specifies the main emphasized points in theories of film therapy and education. It considers the specifics of film therapy in the process of increasing the effectiveness of communication. It discusses the advantages and limitations of the proposed method. The contemporary forms of film therapy and the formats of cinema clubs are criticized. The theoretical assumptions and empirical research that could be used as a basis for a method of developing effective communication by means of films are discussed. Our studies demonstrate that the usage of film therapy must include an educational stage for more effective and stable results. This means teaching viewers how to recognize certain psychotherapeutic and communicative patterns in the material of films, to practice the skill of finding as many examples as possible for each pattern and to transfer the acquired schemes of analyzing and recognizing patterns into one’s own life circumstances. The four stages of the film therapeutic process as well as the effects that are achieved at each stage are described in detail. In conclusion, the conditions under which the usage of the film therapy method would be the most effective are observed. Various properties of client groups and psychotherapeutic scenarios for using the method of active film therapy are described

Hyaluronidase in cosmetology: Evidence-based medicine review [ГИАЛУРОНИДАЗА В КОСмЕТОЛОГИИ: ОБЗОР ДАННЫХ ДОКАЗАТЕЛЬНОЙ мЕДИцИНЫ]

The purpose of the present review was to analyze current data on hyaluronidase application in cosmetology from the standpoint of evidence-based medicine. Clinical evidence suggests a high efficacy of hyaluronidase for the treatment of asymmetry, hypercorrection, migration, filler visualization, Tyndall effect, vascular complications, impaired visual function and delayed reactions. The dilution and volume of the hyaluronidase to be injected varies depending on the specific indication, the volume of the intradermal implant and the manufacturer's recommendations. The most significant contraindication for hyaluronidase preparations in cosmetology is the hypersensitivity, therefore, a drug sensitivity test should be performed before the first use. © 2020 Stavropol State Medical University. All rights reserved

Bioluminescent and spectroscopic properties of His-Trp-Tyr triad mutants of obelin and aequorin.

Ca2+-regulated photoproteins are responsible for the bioluminescence of a variety of marine organisms, mostly coelenterates. The photoproteins consist of a single polypeptide chain to which an imidazopyrazinone derivative (2-hydroperoxycoelenterazine) is tightly bound. According to photoprotein spatial structures the side chains of His175, Trp179, and Tyr190 in obelin and His169, Trp173, Tyr184 in aequorin are at distances that allow hydrogen bonding with the peroxide and carbonyl groups of the 2-hydroperoxycoelenterazine ligand. We replaced these amino acids in both photoproteins by residues with different hydrogen bond donor–acceptor capacity. All mutants exhibited luciferase-like bioluminescence activity, hardly present in the wild-type photoproteins, and showed low or no photoprotein activity, except for aeqH169Q (24% of wild-type activity), obeW179Y (23%), obeW179F (67%), obeY190F (14%), and aeqY184F (22%). The results clearly support the supposition made from photoprotein spatial structures that the hydrogen bond network formed by His–Trp–Tyr triad participates in stabilizing the 2-hydroperoxy adduct of coelenterazine. These residues are also essential for the positioning of the 2-hydroperoxycoelenterazine intermediate, light emitting reaction, and for the formation of active photoprotein. In addition, we demonstrate that although the positions of His–Trp–Tyr residues in aequorin and obelin spatial structures are almost identical the substitution effects might be noticeably different

The intrinsic fluorescence of apo-obelin and apo-aequorin and use of its quenching to characterize coelenterazine binding.

The intrinsic fluorescence of two apo-photoproteins has been characterized and its concentration-dependent quenching by coelenterazine has been for the first time applied to determine the apparent dissociation constants for coelenterazine binding with apo-aequorin (1.2±0.12µM) and apo-obelin (0.2±0.04µM). Stopped-flow measurements of fluorescence quenching showed that coelenterazine binding is a millisecond-scale process, in contrast to the formation of an active photoprotein complex taking several hours. This finding evidently shows that the rate-limiting step of active photoprotein formation is the conversion of coelenterazine into its 2-hydroperoxy derivativ