[Problems and prospects of cell therapy for critical ischaemia of lower limbs].

Background: Cell therapy was proposed as a procedure of indirect revascularization for patients with critical ischaemia of lower extremities for whom endovascular and surgical revascularization is impossible. We present herein a review of the state of the art of studies in the field of cell therapy of this cohort of patients.

Basic Provisions: Cell therapy has proved safe, however, the results of studies of efficacy are relatively ambiguous and unconvincing.

[Functional analysis of the Xist promoter region in mouse Mus musculus].

X-chromosome inactivation which takes place in early embryogenesis of all higher mammals is largely determined by the Xist gene activity. This gene encodes long untranslated RNA, which provides transcriptional silencing of the genes on chromosome. In the present study, three enhancer and three silencing transcriptional elements were identified in the Xist promoter region.

[Comparative analysis of the DXPas34 regulatory region in rodents].

Mouse X chromosome inactivation center contains the DXPas34 minisatellite locus which plays an important role in expression regulation of the Tsix and Xist genes, involved into female dosage compensation. Comparative analysis of the DXPas34 locus from mouse, rat, and four common vole species revealed similar organization of this region in the form of tandem repeat blocks. A search for functionally important elements in this locus showed that all the species examined carried the conservative motif monomers, which could be involved in regulation of X inactivation.

[Role of G(-43)A polymorphism in the promoter region of the Xist gene in non-random X-chromosome inactivation in intraspecific hybrid voles].

Interaction of transcription factor CTCF with the minimal promoter of Xist gene was investigated in intraspecific hybrids ofcommon voles. CTCF was shown to bind with the minimal promoter region in vivo. However, the experiments of the delay in gel resulted in the absence of interaction between the CTCF factor and its potential binding site.

[Investigation of the Tsix gene regulatory region in vole Microtus rossiaemeridionalis].

The Tsix regulatory region was examined in vole Microtus rossiaemeridionalis. The minimal promoter region, three potential enhancer regulatory elements and one transcription suppressor element were identified. The enhancer regions contained potential binding sites of transcription activators, while in the region of putative silencer contained potential binding site of the ARP1 (NR2F2) protein.

[Expression of early developmental genes in vole Microtus rossiaemeridionalis].

The expression of genes Sox2, Klf4, Myc, Sall4, Gata6, Foxa2, Hnf4a, Cdx2, Esrrb, Hand1 in cultivated cells, embryos and organs of adult voles Microtus rossiaemeridionalis was studied. High resemblance of the expression patterns of these genes in the organs of adult voles, mice and humans was demonstrated. It was established that genes Gata6, Foxa2 and Hnf4a were specifically expressed in vole extraembryonic endoderm cells, while Cdx2 and Handl genes, in trophoblast stem cells.

[Induced pluripotent stem cells].

Induced pluripotent stem cells (iPS) result from a reprogramming of somatic cells via transduction with viral vectors expressing the Oct4, Sox2, c-Myc, Klf4, Nanog, and Lin28 genes, which are essential for the establishment and maintenance of the pluripotent state. In properties, iPS are almost fully similar to embryonic stem cells (ESC). To date, iPS have been obtained from various differentiated cells of mice and humans.

[OCT4 and NANOG are the key genes in the system of pluripotency maintenance in mammalian cells].

Embryonic stem cells are able to give rise after differentiation to derivatives of three germinal layers (ectoderm, endoderm, and mesoderm) and to functional gametes. This property of cells is referred to as pluripotency. The pluripotent status of preimplantation embryo cells and embryonic stem cells is maintained by a complicated system of molecular signaling pathways and transcription factors.

[Extraembryonic endoderm stem cell lines from common voles of the genus Microtus].

Twenty-eight independent extraembryonic endoderm (XEN) stem cell lines have been obtained from morula and blastocyst cells of common voles. Most cell lines form very few cell-cell contacts when growing and morphologically correspond to the XEN that were earlier described in mice. In addition, XEN cell lines with atypical morphology forming colonies have been obtained for the first time.

[The structure and evolution of the MaSMC4 gene of common vole Microtus arvalis (Arvicolidae, Rodentia)].

In eukaryotes, the SMC (Structural Maintenance of Chromosomes) gene family is represented by at least six genes. Some of these genes have tissue-specific homologs. Eukaryotic SMC structural proteins are the members of biochemical complexes responsible for cohesion of sister chromatids, recombination, repair, regulation of gene expression, and formation of mitotic chromosomes.

[Chromatin modifications during X-chromosome inactivation in female mammals].

In female mammals, the process of dosage compensation occurs during early embryonic development. As a result of this, one of X-chromosomes becomes transcriptionally inactive. This process is accompanied by chromatin remodeling on inactivated X-chromosome, providing transcriptional silencing of the genes and maintenance of their inactive state.

[Evolution of mammalian sex chromosomes: cooperation of genetic and epigenetic factors].

The X and Y chromosomes of mammals, which significantly differ in structure and genetic composition, are thought to originate from a pair of autosomes. During evolution of sex chromosomes in placental mammals, the degradation of the Y chromosome and inactivation spreading along the X chromosome occurred gradually and in concert. Thus, at the molecular level, the genetic and epigenetic factors interacted toward greater differentiation of the X/Y pair.

[SMC (structural maintenance of chromosomes) structural protein family and their role in chromatin reorganization].

Structural chromatin proteins of the SMC (Structural Maintenance of Chromosomes) family play an important role in structural DNA reorganization in pro- and eukaryotes. Eukaryotic SMC proteins are the core components of the cohesin and condensin complexes. The cohesin complex is responsible for sister chromatid and homolog cohesion in mitosis and meiosis.

[Isolation of ES-like lines of common voles of the genus Microtus from blastocysts and germ cells and as a result of the fusion of somatic cells with mouse embryonic stem cells].

Three and four independent cell lines with limited pluripotency were obtained from the inner cell mass cells of blastocysts and primordial germ cells of common voles, respectively. The results of cytogenetic analysis suggest that all these lines originated from the embryos of F1 Microtus rossiaemeridionalis x M. arvalis males and had a great number of near-triploid cells already during the early passages.

[Gene for structural proteins of the SMC family in the common vole Microtus arvalis].

Genes for four subfamilies of SMC (structural maintenance of chromosomes) proteins have been isolated from the genome of a common vole Microtus arvalis. The high degree of homology between representatives of each SMC protein subfamily of different classes of organisms has been demonstrated. The full-sized copy of a mammalian gene encoding SMC4 protein has been isolated and analyzed for the first time.

[Organization of extended repeats in heterochromatin in sex chromosomes in the common vole species Microtus group "arvalis"].

Two long repeats, MS3 and MS4, are predominantly located in sex-chromosomal heterochromatin in common vole species. Their tandem arrangement was revealed by means of the PCR analysis of genomic DNAs of four Microtus species and by restriction mapping of clones selected from a M. rossiaemeridionalis genomic library.

[High-resolution GTG-banding and nucleolar organizer regions of chromosomes of two vole species: Microtus rossiaemeridonionalis and M. transcaspicus (Rodentia, Arvicolidae)].

With the use of the GTG-banding of prometaphase chromosomes, 503 and 402 segments were revealed in haploid chromosome sets of voles Microtus rossiaemeridionalis and M. transcaspicus, respectively. Based on a detailed study of chromosomes at different condensation levels, idiograms of M.

[High resolution GTG banding and nucleolus organizer regions of chromosomes from the vole Microtus kirgisorum].

The use of GTG-banding of chromosomes in combination with the pipette method of chromosome preparation at the early metaphase made it possible to distinguish about 520 segments in the haploid chromosome set of vole Microtus kirgisorum. The ideogram of M. kirgisorum chromosomes was obtained on the basis of detailed investigation of chromosomes at different condensation levels.

[Prospects for obtaining a mapping panel for somatic cell marsupial-rodent hybrids for the short-tailed opossum Monodelphis domestica].

A possibility of obtaining a panel of marsupial-rodent somatic cell hybrid clones has been explored, with a view to mapping the genome of the opossum (Monodelphis domestica). Fusion of opossum cells (splenocytes, bone marrow cells, and fibroblasts) with fibroblasts of Chinese hamster or vole (HGPRT- and TK- mutants, respectively) produced 146 hybrid clones. The majority of marsupial-mammalian somatic cell hybrids were characterized by pronounced fragmentation and segregation of marsupial chromosomes.

[Mapping the silver fox genome. IV. Determination of chromosomal location of genes for ornithine carbamoyltransferase and prion protein].

The location in chromosomes of genes encoding ornithine carbamoyltransferase (ornithine transcarbamylase, OTC) and prion protein (PrP) was determined by Southern blotting of DNAs obtained from a panel of hybrid (for x Chinese hamster) somatic cell clones, with human OTC and Chinese hamster PrP DNA fragments used as probes. The gene OTC was located in the X-chromosome and PrP was located in chromosome 14 of the fox.

[X chromosome inactivation in mammals].

The most important results of the last 30 years of studies on mammalian X-chromosome inactivation are reviewed. The data on X-chromosome inactivation in cells of embryonic and extraembryonic tissues and in male and female germ cell lines are discussed. Special attention is paid to data on mapping and functioning of the X-inactivation center and of recently discovered gene XIST.