Провели сравнительный анализ захвата радиоактивно меченого дофамина интактными синаптосомами и очищенными синаптическими везикулами, выделенными из дорзального стриатума мышеи с полной инактивацией генов, кодирующих все три синуклеина, и мышеи дикого типа. Отсутствие синуклеинов привело к существенному снижению эффективности захвата этого нейромедиатора синаптическими везикулами, но не повлияло на захват дофамина синаптосомами.

A number of neurodegenerative disorders have recently been coalesced into a group of proteinopathies because of the similarity of molecular mechanisms underlying their pathogenesis. A key step in the development of proteinopathies is a structural change that triggers aggregation of proteins, which are intrinsically prone to form aggregates due to their physical and chemical properties. Present review is devoted to the recent progress in the field of proteinopathies with specific focus on properties of aggregate-prone proteins, main stages of the development of molecular pathology and the role of cellular clearance systems in progression of neurodegeneration. Recent modifications in the nomenclature of neurodegenerative diseases will also be addressed.

На основе сходства молекулярных механизмов патогенеза ряд нейродегенеративных заболеваний был объединен в группу протеинопатий. Эти заболевания развиваются в результате изменений в структуре белков, склонных к образованию агрегатов. Настоящий обзор посвящен анализу современных данных о молекулярных основах развития протеинопатий. В нем рассмотрены общие свойства склонных к агрегации белков, основные этапы развития протеинопатий, обсуждена роль защитных систем клетки в прогрессии протеинопатий и новые подходы к современной классификации нейродегенеративных расстройств, базирующиеся на данных о молекулярном патогенезе нейродегенерации.

A newly found locus of the Drosophila melanogaster genome, named toothrin (tth) has been used to study the role of the conserved domain 2/3 of genes from the d4 family. In contrast to the 2/3 domain of all vertebrates studied (including humans), which is always accompanied by the d4 domain, the tth gene contains the sequence encoding the 2/3 domain but lacks that encoding the d4 domain. The tth gene overexpression has been studied using the two-component system UAS-GAL4. It has been demonstrated that the tth overexpression at the third-instar larval (prepupal) stage decreases survival rate, simultaneously causing a substantial deceleration of development in Drosophila. It is known that the change of developmental stages in Drosophila is controlled by the rates of the expression of ecdysteroid and juvenile hormones (JHs). It is supposed that the overexpression of the tth gene causes either a shift in the ecdysterone-to-JH ratio (through a decreased JH decay rate or a delayed initiation of ecdysone synthesis) or a deceleration of the release of ecdysterones synthesized.

To identify genes differentially expressed in the developing rat cerebellum, a subtractive cDNA cloning procedure, followed by differential screening, was used. Four novel genes, MB, MF, 3E7, and 3C6, the transcriptional activity of which changed by a factor of five during cerebellar development, were isolated. The genes obtained were differentially expressed in different regions of the central nervous system. Variations in the levels of corresponding transcripts in the brain cortex and cerebellum were also recorded during postnatal rat development.

To isolate genes differentially expressed in the rat brain cortex and cerebellum, a subtractive cDNA cloning procedure requiring only small quantities of poly(A+) RNA, followed by differential screening, was used. Two novel genes, MK and 3L7, with cortex- and cerebellum-specific expression were identified. These genes displayed different expression patterns in the brain cortex, cerebellum, and hippocampus during postnatal development.

To isolate genes differentially expressed in the rat brain cortex and cerebellum, a subtractive cDNA cloning procedure requiring only small quantities of poly(A(+)) RNA, followed by differential screening, was used. Two novel genes, MK and 3L7, with cortex- and cerebellum-specific expression were identified. These genes displayed different expression patterns in the brain cortex, cerebellum, and hippocampus during postnatal development.

EcoRI fragments of DNA isolated from the different mouse organs were hybridized to radioactivity labelled probe specific for the gene of oncoprotein p53. The analysis of the blot-hybridization points to the existence of the specific blockage of an EcoRI site flanking a 3.3 kb fragment of DNA including the pseudogene p53, isolated from the skin tissue. The existence of a polymorphous EcoRI site localized distally to the pseudogene p53 has been demonstrated in the DNA of mice of different lines.

Nucleotide sequences that are cleaved by calf thymus type I topoisomerase have been determined using cloned human Ha-ras and p53 genes. Localization and relative frequency of single-strand cleavages within these sequences were observed to change in the presence of the cytotoxic alkaloid camptothecin.

Studies of a-thalassemia, a hereditary blood disease associated with deficient expression of the a-globin gene, have revealed a variety of mutations underlying this condition. So far 40 such mutations have been revealed by various molecular genetic techniques (Kan, 1986). They include point substitutions, deletions and insertions, which affect different stages of the functioning of the a-globin gene. a-thalassemia is believed to be caused by different sets of mutations in diffe~ent ethnic groups. It is important to take this into account when developing diagnostic and prevention approaches for a particular region (Antonarakis et al., 1985). In the Soviet Union 6-thalassemia has been found to occur in Trans­ caucasia, in Central Asia and in the southern European part of the USSR, the incidence being especially high in Azerbaijan (Rustamov et al., 1981). In an earlier study we examined a number of a-thalassemic cases from Azerbaijan, having undertaken an investigation of globin proteins, hybrid­ ization analysis of globin mRNA and restriction mapping of globin gene DNA. None of the cases showed any major deletions or rearrangements in the region of the a-globin genes. At the same time considerable heterogeneity was observed as to the degree of expression of the a-globin genes, mani­ festing itself in a substantial variation of the relative content of 6-globin mRNA and in the varying repression of a-globin protein synthesis (Dergunova et al., 1984). A comparative study of the 6-globin sequences of the nuclear and cyto­ plasmic RNA in erythroid cells of the spleen was performed for one patient. In both cases the amount of a-globin sequences proved to be reduced by a factor of 5 as compared with a-globin sequences. It was supposed that the patient might have a a-globin gene transcription disorder or a disturbance of the earliest stages ~f the a-globin mRNA processing. A DNA library was obtained on the basis of this patient's DNA, with A EMBL4 bacteriophage DNA serving as vector. The library contained about 1 million recombinant clones, which number corresponds to about three human genomes. With this number of clones there is a good likelihood (90%) that any unique clone can be obtained from the library. The average size of human DNA insertions in the recombinant clones is 15-24 kb.

43 cDNA clones specific for murine cellular tumor antigen p53 were isolated from a library constructed using 17S fraction of mRNA from the SV40 transformed murine fibroblasts (SVT2). These clones contain the whole coding region of p53 mRNA and the most of non-translated sequences. A plasmid containing 1.8 kb insert of p53 cDNA was constructed. The p53 specific insert in this plasmid was colinear with p53 mRNA, as revealed by S1 nuclease analysis. 5'-region of the p53 gene comprising non-translated and promoter areas was cloned from the mouse genomic library. A combined clone containing promoter and the whole region, corresponding to p53 mRNA has been constructed.

Two allelic p53 genes were investigated. The allelic gene with BgIII site in the first intron codes for faster p53 protein variant, the other allelic gene coding for slower p53 protein variant (according to the mobility in SDS-PAAG). Exons and flanked regions of introns were sequenced. In coding regions allelic genes only differ by second nucleotides of codon 72 (G----C), which leads to the change in amino acid sequence (Arg----Pro). The relationship of these changes and the function of p53 is discussed.