[Reverse in situ hybridization of DNA probes of anomalous chromosomes in diagnosing chromosome pathologies]. / Obratnaia in situ gibridizatsiia DNK-zondov anomal'nykh khromosom v diagnostike khromosomnykh patologii.

The results of analysis of congenital chromosomal pathologies and chromosomal rearrangements upon the occurrence of haematological diseases, which was involved constructing DNA libraries of abnormal chromosomes and subsequent reverse CISS hybridization have been considered. High effectiveness of this approach for analysis of chromosomal translocations, deletions of chromosomal regions, minor extra chromosomes, and large marker chromosomes with complex organization was shown. The possibility of implementation of this approach and its large-scale application in medical and genetic studies of congenital developmental pathologies and chromosomal diagnostics of haematological diseases has been discussed.

Comparative cytogenetics of hamsters of the genus Calomyscus.

Karyotypes of Calomyscus from different regions of Turkmenistan, Iran, and Azerbaijan were studied using chromosome banding (G- and C-banding) and analyses of meiosis in laboratory hybrids. Extensive variation in the diploid number and the number of autosomal arms (FNa) was revealed (2n = 30, FNa = 44; 2n = 32, FNa = 42; 2n = 44, FNa = 46; 2n = 44, FNa = 58; 2n = 37, FNa = 44; 2n = 50, FNa = 50; 2n = 52, FNa = 56). Centric and tandem fusions and heterochromatin changes were identified as the major modes of karyotype evolution in this group. Natural hybrids between individuals with different karyotypes were recorded, and regular chromosome pairing in meiosis was observed in laboratory hybrids. Fluorescence in situ hybridization with a 353-bp BspRI complex tandem repeat indicated that chromosomal repatterning occurred recently within the genus. There is no unequivocal evidence suggesting the role of chromosomal change in the speciation of the populations of Calomyscus examined.

Organization and chromosomal localization of a B1-like containing repeat of Microtus subarvalis.

A repetitive DNA sequence, MS2, was isolated from EcoRI-digested genomic DNA of the vole, Microtus subarvalis. The fragment was cloned and sequenced. Sequence analysis of this 1194-bp fragment revealed a 156-bp region demonstrating a 55% homology with the mouse B1 repeat. The remaining MS2 sequence shows no significant homology with other known GenBank sequences. The results of in situ hybridization of MS2 on vole metaphase chromosomes indicate the fragment is confined to heterochromatin blocks of the sex chromosomes in all but one species (M. arvalis). Distribution of MS2 sequences provides evidence for heterogeneity of the giant heterochromatin blocks of the XY Chromosomes (Chrs) in voles, for the unique cluster-like localization of MS2 within these blocks.

Localization of rat K51 keratin-like locus (Krt10l) to human and animal chromosomes by in situ hybridization.

The rat K51 locus (gene symbol Krt10l) was mapped using isotopic in situ hybridization to rat chromosome 3, human chromosome 9, pig chromosome 6, cattle chromosome 18, and mink chromosome 1.

[Modification of DNA with 4-aminooxybutylamine as a method for obtaining highly-sensitive hybridization probes. Mapping of the gene for human chorionic somatomammotropin hormone]. / Modifikatsiia DNK 4-aminooksibutilaminom kak sposob polucheniia vysokochuvstvitel'nykh gibridizatsionnykh zondov. Lokalizatsiia gena khorionicheskogo somatomammotropnogo gormona cheloveka.

A new method for preparation of highly sensitive nonradioactive probes for dot, dot-blot and in situ hybridization was developed. The method is based on chemical modification (transamination) of cytosine residues with 4-aminooxybutylamine following by coupling biotin or fluorescein to aliphatic aminogroups introduced into DNA. Such a probe have been used for detection of gene encoding chorionic somatomammotropin hormone (hCS) in genomic blot hybridization. The gene hCS was mapped using isotopic and nonisotopic in situ hybridization on human chromosome 17.

Pattern of X-Y chromosome pairing in microtine rodents.

Pairing of X and Y chromosomes at meiotic prophase in 14 species of the subfamily Microtinae (Clethrionomys rufocanus, C. rutilus, C. glareolus, Arvicola terrestris, Microtus guentheri, M. socialis, M. afghanus, M. bucharicus, M. oeconomus, M. arvalis, M. rossiaemeridionalis, M. kirgisorum, M. transcaspicus, M. (Pitymys) majori) was analysed in relation to their taxonomic position and variation in the morphology of their sex chromosomes. The sex chromosomes formed a synaptonemal complex (SC) at pachytene in all Clethrionomys species, Arvicola terrestris, and M. oeconomus, while they did not pair at all in M. (Pitymys) majori, Microtus socialis, M. guentheri, M. afghanus, M. bucharicus, M. arvalis, M. rossiaemeridionalis, M. kirgisorum, and M. transcaspicus. The X chromosome of these species varied in centromere position independently of pairing pattern. Insertion of heterochromatin of different size and location was found in some, but not in all species with asynaptic sex chromosomes. It is suggested that the sex chromosomes lost their ability to pair at male meiosis in the common ancestor of palearctic species of the genus Microtus. This event was not caused by a gross chromosomal rearrangement.

[An unusual heteromorphic bivalent in the common vole (Microtus arvalis) from Byelarus]. / Neobychnyi geteromorfnyi bivalent u obyknovennykh polevok (Microtus arvalis) iz Belorussii.

Electron microscopic analysis was carried out on the synaptonemal complexes of ten male common voles (Microtus arvalis) caught of 1990 in Byelorussia. In the early pachytene stage of spermatocytes of four males heteromorphic bivalent has been found in one of five large autosomes. In the central region of the bivalent one of the lateral elements is in the form of a D-loop, characteristic of insertion/deletion heterozygotes. However, high-resolution G-band staining of mitotic chromosomes from fibroblasts showed no significant differences in the G-band patterns between homologues.

Unusual heteromorphic bivalents in the common vole (Microtus arvalis) from Belorussia.

Electron microscopic analysis was carried out on the synaptonemal complexes of 10 male common voles (Microtus arvalis) caught in 1990 in Belorussia. In the early pachytene stage of spermatocytes of four males, a heteromorphic bivalent has been found in one of five large autosomes. In the central region of the bivalent one of the lateral elements is in the form of a D-loop, characteristic of insertion/deletion heterozygotes. However, high-resolution G-band staining of mitotic chromosomes from fibroblasts shows no significant differences in the G-band pattern between homologs.

[Role of nucleases in the origination of chromosomal disorders in virus-infected cells]. / Rol' nukleaz v vozniknovenii khromosomnykh narushenii v kletkakh, zarazhennykh virusom.

It is shown that herpes simplex virus can induce the chromosome aberrations both in cells supporting the productive infection and in non-permissive cells. In virus-infected human embryo fibroblast culture the activity of cell (lysosomal) and virus-coded DNAses is elevated. Suppression of the activity of any of the enzymes leads to decreasing the number of aberrant cells. Suppression of the activity of both DNases at the same time decreases the number of aberrant cells to a control level. In M15 cells which do not support the productive infection, the activity of only lysosomal DNase is elevated. Suppression of its activity leads to the decrease of the frequency of cells with chromosome breaks to a control level. Thus, both cells and virus-coded lytic enzymes can participate in the production of chromosome breaks in virus-infected cells. Possibly, the relative role of these enzymes may be rather different in different virus-cell systems.

[DNA degradation of cultured mammalian cells infected with herpes simplex virus]. / Degradatsiia DNK kul'tiviruemykh kletok mlekopitaiushchikh pri zarazhenii virusom prostogo gerpesa.

In connection with a supposition concerning the role of nucleases in the production of chromosome breaks in the herpes simplex virus-infected cells, the stability of DNA of the infected cultured cells was studied. It was established that the infection of cells with herpes simplex virus resulted in a partial degradation of cellular DNA of permissive and non-permissive cells. In human embryo fibroblast culture products of hydrolysis of cellular DNA may be reutilized by the synthetising virus. In cells of clone M15, in which no mature virus is produced, products of hydrolysis of DNA are revealed in acid-soluble pool. The observed degradation of DNA apparently is not associated with the cell death. It cannot be excluded that a partial degradation of DNA in the cell due to viral infection may bring about a production of visible chromosome breaks.

[Reasons for development of chromosome aberrations in cells of a culture of human embryonal fibroblasts infected with herpes simplex virus]. / Izuchenie prichin vozniknoveniia khromosomnykh aberratsii v kletkakh kul'tury émbrional'nykh fibroblastov cheloveka, zarazhennoi virusom prostogo gerpesa

The object of this investigation was the role of lysosomic and virus-induced aberrations in cells of the culture of embryonic human fibroblasts infected with herpes simplex virus. It was established that the frequency of cells with chromosomal abnormalities in infected cultures in 4 and 9 hours after infection was 15,2% and 23,7% respectively, being 2% in the control culture. Stablization of lysosomal membranes with hydrocortisone or the inhibition of lysosome enzymes by trypan blue resulted in the decrease of the proportion of aberrant cells down to the control level in 4 hours after the infection, while in 9 hours after the infection it was higher, than in the control, although significantly lower, than in the cultures infected with the virus, but not subjected to any treatment suppressing the mutagenic effect of the virus. The suppression of the transcription of the viral genome by actinomycin D did not decrease the proportion of aberrant cells in 4 hours after the infection, while in 9 hours after the infection it was significantly lower, than in the infected cultures not treated with actinomycin D, but higher, than in the control. Simultaneous suppression of the effect of virus-induced enzymes by actinomycin D and lysosome enzymes by hydrocortisone or trypan blue decreased efficiently the proportion of aberrant cells down to the control level both after 4 and after 9 hours following the infection. Apparently chromosome aberrations in embryonic human fibroblasts infected with herpes simplex virus are caused both by lysosomal and by virus-induced enzymes. Possibly in different virus-cell systems the relative role of these two factors can be considerably different from one another.