Live Birth of a Healthy Child in a Couple with Identical mtDNA Carrying a Pathogenic c.471_477delTTTAAAAinsG Variant in the MOCS2 Gene.

Molybdenum cofactor deficiency type B (MOCODB; #252160) is an autosomal recessive metabolic disorder that has only been described in 37 affected patients. In this report, we describe the presence of an in-frame homozygous variant (c.471_477delTTTAAAAinsG) in the MOCS2 gene in an affected child, diagnosed with Ohtahara syndrome according to the clinical manifestations. The analysis of the three-dimensional structure of the protein and the amino acid substitutions suggested the pathogenicity of this mutation. To prevent transmitting this mutation to the next generation, we used preimplantation genetic testing for the monogenic disorders (PGT-M) protocol to select MOCS2 gene mutant-free embryos for transfer in an in vitro fertilization (IVF) program. As a result, a healthy child was born. Interestingly, both parents of the proband shared an identical mitochondrial (mt) DNA control region, assuming their close relationship and thus suggesting that both copies of the nuclear rare variant c.471_477delTTTAAAAinsG may have been transmitted from the same female ancestor. Our estimation of the a priori probability of meeting individuals with the same mtDNA haplotype confirms the assumption of a possible distant maternal relationship among the proband's direct relatives

Study of the effect of the introduction of mitochondrial import determinants into the gRNA structure on the activity of the gRNA/SpCas9 complex in vitro

It has long been known that defects in the structure of the mitochondrial genome can cause various neuromuscular and neurodegenerative diseases. Nevertheless, at present there is no effective method for treating mitochondrial diseases. The major problem with the treatment of such diseases is associated with mitochondrial DNA (mtDNA) heteroplasmy. It means that due to a high copy number of the mitochondrial genome, mutant copies of mtDNA coexist with wild-type molecules in the same organelle. The clinical symptoms of mitochondrial diseases and the degree of their manifestation directly depend on the number of mutant mtDNA molecules in the cell. The possible way to reduce adverse effects of the mutation is by shifting the level of heteroplasmy towards the wild-type mtDNA molecules. Using this idea, several gene therapeutic approaches based on TALE and ZF nucleases have been developed for this purpose. However, the construction of protein domains of such systems is rather long and laborious process. Meanwhile, the CRISPR/Cas9 system is fundamentally different from protein systems in that it is easy to use, highly efficiency and has a different mechanism of action. All the characteristics and capabilities of the CRISPR/Cas9 system make it a promising tool in mitochondrial genetic engineering. In this article, we demonstrate for the first time that the modification of gRNA by integration of specific mitochondrial import determinants in the gRNA scaffold does not affect the activity of the gRNA/Cas9 complex in vitro

НАРУШЕНИЯ ЭКСПРЕССИИ МРНК HSP27 И УБИКВИТИНА КАК МЕХАНИЗМ УСКОЛЬЗАНИЯ ОПУХОЛЕВЫХ КЛЕТОК ЛИНИИ JURKAT ОТ АПОПТОЗА

The research objective is to establish the link between heat shock protein 27 and ubiquitin mRNA expression as well as Jukart tumor cell apoptosis.The method of flow cytofluorometry has been used to evaluate apoptosis realization using FITC-labeled annexin V and propidium iodide along with the amount of reactive oxygen species. Spectrofluorimetry has been applied to register the caspase-3 activity. The content of hydroxyl radicals has been determined by spectrophotometry. The level of ubiquitin and heat shock protein 27 mRNA expression has been identified using real-time PCR. Intact Jukart tumor cells and blood lymphocytes of healthy donors served the material for the research.Following the carried out research it has been found out that the fall in the amount of annexin V positive cells and the reduced caspase-3 activity were accompanied by the rise in the content of hydroxyl radicals and reactive oxygen species against the backdrop of the increased heat shock protein 27 and ubiquitin mRNA expression in Jukart tumor cells.Цель исследования – установить взаимосвязь между экспрессией мРНК белка теплового шока 27, убиквитина и реализацией апоптоза в опухолевых клетках линии Jurkat.Методом проточной цитофлюориметрии проводили оценку реализации апоптоза с использованием FITS-меченного аннексина V и пропидия иодида, количества активных форм кислорода, спектро¬флюориметрическим методом регистрировали активность каспазы-3. Содержание гидроксильного радикала определяли спектрофотометрическим методом. Уровень экспрессии мРНК убиквитина и белка теплового шока 27 – с помощью полимеразной цепной реакции в реальном времени. Материалом для исследования служили интактные опухолевые клетки линии Jurkat и лимфоциты крови здоровых доноров.В результате проведенного исследования установлено, что снижение количества аннексин-положительных клеток и активности каспазы-3 сопровождалось увеличением содержания гидроксильного радикала и активных форм кислорода на фоне усиления экспрессии мРНК белка теплового шока 27 и убиквитина в опухолевых клетках линии Jurkat

Mitochondrial DNA as a Factor of Glaucomous Optic Neuropathy’s Development Mechanism

Currently, the mitochondrial component is becoming increasingly significant in the development and progression of glaucoma optic neuropathy. Since mitochondria have their own genetic apparatus, the study of qualitative and quantitative changes in mitochondrial DNA (mtDNA) becomes part of the disease diagnosis, in addition to studying the functional characteristics of the organelles alone. Moreover, the inability to explain the nature of the disease by known mutations of nuclear DNA contributes to the the study of mtDNA. In this review, we briefly discuss the mitochondrial genetics and the role of mitochondrial haplogroups in the diseases manifestation. We summarize the accumulated data on the qualitative and quantitative changes in mtDNA in patients with glaucoma. We discuss the approach to prevent the inheritance of mutant mtDNA as a part of assisted reproductive technologies, as well as the first steps towards the mtDNA heteroplasmy level manipulation and direct mtDNA editing

Mitochondrial Genome Diversity in Arctic Siberians, with Particular Reference to the Evolutionary History of Beringia and Pleistocenic Peopling of the Americas

Through extended survey of mitochondrial DNA (mtDNA) diversity in the Nganasan, Yukaghir, Chuvantsi, Chukchi, Siberian Eskimos, and Commander Aleuts, we filled important gaps in previously unidentified internal sequence variation within haplogroups A, C, and D, three of five (A–D and X) canonical mtDNA lineages that defined Pleistocenic extension from the Old to the New World. Overall, 515 mtDNA samples were analyzed via high-resolution SNP analysis and then complete sequencing of the 84 mtDNAs. A comparison of the data thus obtained with published complete sequences has resulted in the most parsimonious phylogenetic structure of mtDNA evolution in Siberia-Beringia. Our data suggest that although the latest inhabitants of Beringia are well genetically reflected in the Chukchi-, Eskimo-Aleut-, and Na-Dene-speaking Indians, the direct ancestors of the Paleosiberian-speaking Yukaghir are primarily drawn from the southern belt of Siberia when environmental conditions changed, permitting recolonization the high arctic since early Postglacial. This study further confirms that (1) Alaska seems to be the ancestral homeland of haplogroup A2 originating in situ approximately 16.0 thousand years ago (kya), (2) an additional founding lineage for Native American D, termed here D10, arose approximately 17.0 kya in what is now the Russian Far East and eventually spread northward along the North Pacific Rim. The maintenance of two refugial sources, in the Altai-Sayan and mid-lower Amur, during the last glacial maximum appears to be at odds with the interpretation of limited founding mtDNA lineages populating the Americas as a single migration