[Molecular mechanisms of impaired antigenic presentation as a cause of tumor escape from immune surveillance]. / Molekulyarnye mekhanizmy narusheniya prezentatsii antigena kak prichiny uskol'zaniya opukholi ot deistviya immunnogo nadzora.

The review summarizes data on the features of antigen presentation in tumor cells. The molecular mechanisms of the antitumor immune response are considered with an emphasis on the ability of tumor cells to avoid the action of immune surveillance. The features of expression of MHC molecules depending on treatment regimens are provided. Ways to improve existing and create new treatment regimens aimed at elimination of tumor cells because of antitumor immune response are discussed.

Features of Distribution of the Allelic Variant of the OAS1 Gene Associated with Severe Form of the Coronavirus Infection in the Russian and Global Populations.

The study of the geographic distribution of the allelic variant of the OAS1 gene associated with severe form of the infections caused by RNA viruses was carried out using the rs10774671 polymorphic locus. The mutant allele encoding the p42 protein isoform was most prevalent in the Russian populations. A comparative analysis of the prevalence of the mutant allele in world populations showed that its frequency is 0.9 among the inhabitants of Northern Eurasia, while the allele encoding the p46 protein isoform is widespread among the population of West Central Africa. A cartographic analysis of the relationship between the population-frequency characteristics of the marker alleles and the geographical remoteness of the populations showed that the mutant allele is most often observed in the indigenous populations of the Far East, which suggests its East Asian origin.

[Mitochondrial DNA Polymorphism in Different Populations of Spangled Orloff Chickens].

For the first time, the genetic diversity of the Spangled Orloff chickens was studied by analyzing the polymorphism of the hypervariable region in the D-loop of mitochondrial DNA (mtDNA). Samples for the analysis were collected at the farms ofthe All-Russia Poultry Research and Technological Institute (VNITIP), the All-Russia Institute of Farm Animal Genetics and Breeding (VNIIGRZh), and the Moscow Zoo. The D-loop partial sequences (between nucleotide positions 57 and 523) were determined according to the reference sequence of Gallus gallus spadiceus mtDNA, NC_007235 in 39 individuals obtained from these populations (GenBank Accession Nos. KM391754-KM391792). In the analyzed mtDNA fragment, a total of 20 polymorphic sites localized between positions 167 and 368, as well as at position 446, were described in Spangled Orloff chickens. One polymorphic site at position 221 (haplogroup E, haplotype ORL-2) was unique. All of the identified nucleotide changes were transition-type substitutions. Overall, based on the analysis of poly- morphic sites in the hypervariable fragment of the D-loop of Spangled Orloff chicken mtDNA, we found seven haplotypes belonging to four haplogroups (A, B, C, and E). Haplogroup E (haplotypes ORL-1, ORL-2, and ORL-3) was present in the majority of the studied individual, with the frequencies of 0.77 in the total sample and 0.47 in the VNIIGRZh farm population. Haplogroups A (haplotypes ORL-4 and ORL-7), B (ORL-6), and C (ORL-5) were found only in samples from the VNIIGRZh farm. The studied mtDNA region revealed a lower level of polymorphism in the VNITIP and Moscow Zoo populations, which only had the ORL-1 and ORL-3 haplotypes belonging to Haplogroup E, respectively. Our data suggested that the studied Spangled Orloff chicken populations differed in the composition and frequencies of mtDNA haplogroups and haplotypes.

A micro-dissection approach for isolation of NotI linking clones from regions frequently deleted in RCC and SCLC.

We demonstrate that micro-dissection can be used for isolating NotI linking clones from the human 3p21-pter region. This approach is an improvement to positional cloning techniques, since NotI linking clones are directly linked with genes.

5S rRNA gene hybridizes to human chromosome 1 at two sites (1q42.11-->q42.13 and 1q43).

Hybridization of a loach (Misgurnus fossilis) oocyte 5S rRNA gene repeat with human chromosomes was carried out to refine the localization of the 5S RNA gene in the human genome. Preliminary in situ hybridization analysis showed that this repeat hybridized with human chromosome region 1q42-->q43, the same location previously reported for the human 5S rRNA gene. High-resolution banding revealed the presence of two sites of hybridization, with a main peak in chromosome region 1q42.1 and a second peak in 1q43. These results are consistent with our data on the existence in the human genome of different 5S rRNA gene clusters specified by BamHI and HindIII restriction sites in spacer DNA (Timofeeva et al., 1993) and suggest a multicluster organization of the human 5S rRNA genes.

[A beta-casein gene fragment is located in region 1p3 of human chromosome 1]. / Fragment beta-kazeinovogo gena lokalizovan v oblasti 1p3 pervoi khromosomy cheloveka.

Analysis of the nucleotide sequence of a cloned fragment of the human beta-casein gene was performed. A conserved DNA locus, present with a varying degree of degeneracy in introns of [beta]-casein genes of several species and in the intron of an oncogene of the sarc family, was revealed. It was located in region 1p31-32 by means of in situ hybridization. A clearly visible additional hybridization site was observed in region 1p36. The data obtained are discussed in the light of available information on several oncogenes that are located in region 1p3. A relation was found between this region and the occurrence of some cancers, including breast cancer.

[Organization of a 5S ribosomal RNA gene cluster in the human genome]. / Organizatsiia klastera genov 5S ribosomnykh RNK v genome cheloveka.

Method in situ hybridization was used to localize 5S rRNA genes on human chromosomes. It was shown that 5S genes are situated on the 1-st chromosome, positions q42.11-42.13 and q 43. The genome organization of 5S rRNA gene cluster was tested by blot-hybridization of fibroblast DNA restriction fragments separated by electrophoresis. It was shown that cluster comprises of repeats with different length and restriction site specificity. The size of HindIII individual repeats-2.6 kb, BamHI-repeats-2.3 and 1.8 kb. The most part of 5S repeats were organized in oligomers. Long 5S rDNA fragments (100 kb) in which BamHI, HindIII, and AccI restriction sites are absent were demonstrated. The results obtained allow to suggest the multicluster organization of human 5S rRNA genes, these clusters are localized in a short distance from each other on the long arm of 1-st chromosome.

Transfer of foreign DNA into the cells of developing mouse embryos by microprojectile bombardment.

Mouse cells of developing embryos at the 2-4 cell, morula and blastocyst stages, were bombarded by high velocity tungsten microprojectiles. About 70% of developing embryos survived the bombardment. The general embryo structure did not change as a result of the bombardment. Penetration of the tungsten microparticles into the embryo cell nuclei was found at all stages being investigated, and tungsten particle localization on mitotic chromosomes was demonstrated. The total DNA of the mice born from the bombarded embryos was analyzed by dot-blot hybridization and PCR with post-hybridization. The most important results were obtained in experiments with blastocysts. In three cases of blastocyst bombardment, the presence of transferred plasmid DNA (pSV3-neo) was revealed. Transfected cells were shown to be located in the fetal membrane as well as in the embryo. The bombardment of mouse culture cells resulted in their transfection and the production of G418-resistant clones.

[Use of high velocity mechanical injection for the transfer of foreign DNA into early mouse embryos]. / Ispol'zovanie vysokoskorostnoi mekhanicheskoi in"ektsii dlia perenosa chuzherodnoi DNK v rannie émbriony myshei.

The possibility of high velocity mechanical transfer of foreign DNA into inner cell mass of mouse blastocyst was shown. Penetration of tungsten microparticles into early embryo cell nuclei and their localization on mitotic chromosomes was demonstrated. About 70% of developing embryos survived the bombardment. Total DNA of the mice born from bombarded embryos was analyzed by blot-hybridization and PCR with Southern hybridization. In three cases, the presence of the transferred plasmid DNA (pSV3-neo) was revealed.

The delivery of foreign genes into fertilized fish eggs using high-velocity microprojectiles.

Fertilized eggs of loach (Misgurnus fossilis), rainbow trout (Salmo gairdneri) and zebrafish (Brachydanio rerio) were bombarded with high-velocity tungsten microprojectiles covered with plasmid DNA containing sequences of beta-galactosidase and neomycin phosphotransferase genes. About 70% of the eggs survived the bombardment. The activity of both transferred genes was revealed in the fish developed from the bombarded eggs. Neomycin phosphotransferase gene sequences were detected by means of PCR amplification and Southern hybridization in the total DNA of zebrafish that survived after G418 treatment.

High-velocity mechanical DNA transfer of the chloramphenicolacetyl transferase gene into rodent liver, kidney and mammary gland cells in organ explants and in vivo.

Mouse and rat liver, kidney and mammary gland explants were bombarded with high-velocity microprojectiles carrying a chloramphenicolacetyl transferase gene under different promoters (pTAT-cat, p chi-Casein-cat, p beta-Casein-cat). The expression of a CAT gene was revealed in all organ explants 24 h after transfection. The most pronounced expression was found when a TAT-CAT construction was used. In experiments in vivo rat liver was bombarded in situ with microprojectiles carrying pTAT-cat DNA. A marked activity of the CAT gene was detected 24 h after the bombardment.

[High velocity mechanical injection of foreign DNA into fish oocytes]. / Vysokoskorostnaia mekhanicheskaia in'ektsiia chuzherodnoi DNK v iaitsekletki ryby.

High-velocity tungsten microprojectiles were used to introduce into fertilized eggs of loach (Misgurnus fossilis), Rainbow trout (Salmo gairdneri Rich.) and Zebra fish (Brachydanio rerio) DNA sequences of beta-galactosidase and neomycin phosphotransferase genes. No more than 30% of fish oocytes died as a result of bombardment. Experiments revealed marked activity of both enzymes in developing fishes. Neo gene DNA sequences were found in total danio DNA using PCR technique.