[Regulation of Retrotransposons in Drosophila melanogaster Somatic Tissues].

Regulation of retrotransposon activity in somatic tissues is a complex mechanism that has still not been studied in detail. It is strongly believed that siRNA interference is main mechanism of retrotransposon activity regulation outside the gonads, but recently was demonstrated that piRNA interference participates in retrotransposon repression during somatic tissue development. In this work, using RT-PCR, we demonstrated that during ontogenesis piRNA interference determinates retrotransposon expression level on imago stage and retrotransposons demonstrate tissue-specific expression. The major factor of retrotransposon tissue-specific expression is presence of transcription factor binding sites in their regulatory regions.

[A Study of the Fertility of a Drosophila melanogaster MS Strain with Impaired Transposition Control of the gypsy Mobile Element].

The flamenco locus is one of the main components of the piRNA pathway of regulation of mobile genetic elements (MGEs) in Drosophila melanogaster. Mutations at this locus lead to an increase in the transposition activity of MGEs and, as a result, to genetic instability. In this paper, the fertility of a genetically unstable MS strain obtained more than 25 years ago and characterized by a mutation in the flamenco locus and the presence of a functionally active copy of gypsy retrotransposon was investigated. Complex violations of the ovarian morphology were revealed in the MS strain in females: defects in the follicular layer and ring channels, as well as degradation of trophocytes, which in turn led to a decrease in reproductive abilities. Analysis of the MS strain transcriptome showed a decrease in the expression level of 40 genes encoding chorionic proteins and expression specificity at different stages of follicle development. In the F1 and F2 hybrid females from the crosses of MS females with wild type males, restoration of reproductive abilities was observed, despite the fact that half of the F2 females had the flamenco genotype and genetic instability caused by transposition of gypsy (according to the ovo^(D) test). Moreover, the frequency of gypsy transposition in the hybrid F2 females with the flamenco genotype doubled in comparison with the MS strain females. Thus, the MS strain had acquired partial suppression of the flamenco phenotype and accumulated several recessive mutations in the genes that control oogenesis after cultivation for over 25 years.

[On the problem of female infertility: A search for genetic markers].

In every one case out often, the reason behind female infertility turns out to be an orphan disease called 'hypogonadotropic hypogonadism', the single symptom of which is the reduced level of gonadotropins and, as a consequence, amenorrhea in females. Most often, hypogonadotropic hypogonadism is caused by disorder in secretion of gonadoliberin, the product of gene GNRH1. However, the disease is heterogeneous one, so it may origin from either genetic or non-genetic causes. To study the genetic component of the disease pathogenesis, we conducted molecular-genetic analysis of 11 gene-candidates controlling synthesis and secretion of gonadoliberin as well as several gene-candidates functioning as neurodevelopmental and neuroendocrine regulators. In the study participated a group of patients afflicted by hypogonadotropic hypogonadism of an isolated form (n = 10), and a control group of healthy women (n = 20). All women were of reproductive age, with no detected mutations in gene-candidates that could cause any pathological effect. The data on gene-candidates expression in white blood cells are indicative of an increased expression of gene GNRH1 in the sampled patients as compared to the control group (p < 0.05). Other genes demonstrate heterogeneous expression both in the patients group and the control group. Thus, increased expression of gene GNRH1 in blood cells appears to be associated with the isolated form of hypogonadotropic hypogonadism and, in prospect, may be used as one of the disease markers.

Expression of hp1 family genes and their plausible role in formation of flamenco phenotype in D. melanogaster.

Results of expression analysis of transcription of the flamenco locus that controls transposition of the mobile genetic element gypsy, RNA interference system genes ago3, zuc, aub, and HP1 heterochromatin protein family genes hp1a, hp1b, hp1c, hp1d (rhino), and hp1e in D. melanogaster SS strain mutant on the flamenco gene are presented. We show that the number of transcripts in the SS strain that are formed in the flamenco locus is unchanged in some freely chosen points, and this is different from the wild-type strain where a decreased number of transcripts is observed, which clearly is a result of processing of the flamenco locus primary transcript, a predecessor of piRNA. At the same time, expression of genes of the RNA interference system is not affected, but there is a reduced level of hp1d gene expression in ovary tissue. We suggest that the hp1d gene product is directly or indirectly involved in the flamenco locus primary transcript processing.

Domesticated retroviral GAG gene in Drosophila: new functions for an old gene.

The domestication of foreign genes is a powerful mechanism for new gene formation and genome evolution. It is known that domesticated retroviral gag genes in mammals not only take part in protecting against viral infection but also control cell division, apoptosis, function of the placenta, and other biological processes. In this study, we focused on the domesticated retroviral gag gene homolog (Grp) in the Drosophila melanogaster genome. According to the results of a bioinformatic analysis, the Grp gene product is primarily under purifying selection in Drosophilidae family. The Grp protein has been shown to be transmembrane. The Grp gene is expressed at the adult stage of D. melanogaster in gender-specific and tissue-specific manner. Also the Grp gene expression is increased in response to the gypsy retrovirus. A function of the protein as a component of the endosomic membrane is considered.

[Outcomes after one-stage repair of coarctation of the aorta and combined intracardiac lesions in infants].

BACKGROUND: The aim of the study was to compare the outcomes of hypothermic circulatory arrest (GCA) and selective cerebral perfusion (SCP). PATIENTS AND METHODS: Nine patients were treated at the Bakoulev Center for Cardiovascular Surgery. All congenital heart diseases were repaired simultaneously. Group 1 (n = 4) included infants who were treated using an HCA, and the patients who underwent repair with the use of SCP were in group 2 (n = 5). RESULTS: One patient (25%) in group 1 died in the period of thirty days after the repair. Moderate heart failure and respiratory failure occurred postoperatively with no significant difference between two groups. Recoarctation was a frequent (75%) complication after the "end to end" anastomosis creating. One patient (25%) was reoperated on day 3 after the primary repair. Two other patients (50%) were treated by balloon angioplasty. There was relatively high (75%) incidence of a prolonged open sternotomy in group 1. CONCLUSION: There were similar results in HCA and SCP groups. A tendency for frequent prolonged open sternotomy application after HCA surgery as well as occurrence of the recoarctation after "end to end" anastomosis creating was found.

[Clinical and morphological parallels in mitral valve disorders in infants with atrioventricular defect].

Mitral valves tissue samplings from children with complete (13 patients) and partial (6 patients) atrioventricular defects at the age of from I month to 3 years old were examined. The biopsy material was received during the repeat surgical operation on mitral valve, performed due to residual mitral valve regurgitation grade 3-4 at the period of time from 2 days to 1 year after radical defect correction. On histological examination the areas of myxomatous tissue degeneration occupying more than 50% of mitral valves surface were found in 6 (32%) of the 19 patients. There were dispersed star-shaped cells, architectonics disturbances, deposition of acid mucopolysaccharides and increased content of matrix metalloproteinase 13 in such areas of myxomatous degeneration. The sizes of these areas correlated with mitral valve regurgitation grade. After the radical correction of atrioventricular defect the sutures on the folds and fibrous ring of the mitral valve "cut through" reliably more often in patients with wider areas of myxomatous degeneration, which indicates poor prognosis. According to the ultrastructural classification the majority of mitral valve cells regarded as fibroblasts; there also were found cells with the signs of myogenic differentiation--myofibroblasts and isolated hystiocytes. According to the immunohistochemistry assay the cells phenotype regarded as fibroblastic and endothelial differentiation; in some patients there were found cells of smooth muscle origin.

Resident cardiomyocyte precursor stem cells in the myocardium of infants of the first two years of life with tetralogy of Fallot.

We studied the content of resident myocardial stem cells, cardiomyocyte precursors, in myocardial biopsy specimens from the right ventricular outflow tract of patients of the first two years of life with tetralogy of Fallot. Myocardial resident stem cells were detected by the method of confocal immunohistochemistry using antibodies to c-kit and sarcomeric α-actin. The diameter of right ventricular cardiomyocytes was measured; the presence of myolysis zones was semiquantitatively evaluated. Electron microscopic analysis of right ventricular cardiomyocytes was performed. The data on the content of resident myocardial stem cells were compared with clinical and functional parameters of the patients and morphological peculiarities of the myocardium. C-kit-positive resident myocardial stem cells were detected in the right ventricle of 17.4% patients with tetralogy of Fallot. The content of resident myocardial stem cells in these patients varied from 4 to 45 (median 11) per 1 mln cardiomyocytes; this parameter was higher in patients with high content of small cardiomyocytes (diameter <10 µ) and cardiomyocytes with incomplete myofibril assembly in the right ventricular myocardium.

[Study of the transcriptional and transpositional activities of the Tirant retrotransposon in Drosophila melanogaster strains mutant for the flamenco locus].

Transpositions of the gypsy retrotransposon in the Drosophila melanogaster genome are controlled by the flamenco locus, which is represented as an accumulation of defective copies of transposable elements. In the present work, genetic control by the flamenco locus of the transcriptional and transpositional activities of the Tirant retrotransposon from the gypsy group was studied. Tissue-specific expression of Tirant was detected in the tissues of ovaries in a strain mutant for the flamenco locus. Tirant was found to be transpositionally active in isogenic D. melanogaster strains mutant for the flamenco locus. The sites of two new insertions have been localized by the method of subtractive hybridization. It has been concluded from the results obtained that the flamenco locus is involved in the genetic control of Tirant transpositions.

[Translational analysis of the Grp gene, a genomic homologue of the Gag gene of the gypsy retrotransposon of Drosophila melanogaster].

The only open reading frame (ORF) (CG4680) encoding the Gag related protein (Grp) gene, a homologue of gag retrotransposons with long terminal repeats (LTR retrotransposons) of the gypsy group, has been found in the Drosophila melanogaster genome. Earlier, it was shown that the gene was expressed at the transcriptional level only in adult D. melanogaster. The Grp gene has been demonstrated to be a functional gene in the D. melanogaster genome, bit its function is yet to be determined.

[Transcriptional analysis of the Grp gene, a genomic homolog of the retrotransposon gypsy gag gene, in Drosophila melanogaster].

In the present work, we studied the Grp gene (CG4680, Gag related protein) expression at the transcriptional level. It was found that at the embryonic and larval stages of D. melanogaster development the Grp expression proceeds at a low level, but it significantly increases at the adult stage. Adult individuals display a tissue-specific expression: an eleveated level of transcription is observed in the gut tissues, but not in the chitin carcass, head, and gonads. Since the gut may potentially be a primary barrier for the penetration of a viral infection, we conducted a comparative analysis of Grp gene transcription in D. melanogaster strains differing in the presence of active copies of the gypsy errantivirus and in the status of the flamenco gene controlling sensitivity to errantiviral infections. No noticeable differences in the level of Grp gene transcription were revealed. Thus, the Grp gene is not a pseudogene, but it is a functional gene of the D. melanogaster genome whose role remains to be elucidated.

Integration specificity of LTR-retrotransposons and retroviruses in the Drosophila melanogaster genome.

Integration of DNA copies in a host genome is a necessary stage in the life cycle of retroviruses and LTR-retrotransposons. There is still no clear understanding of integration specificity of retroelements into a target site. The selection of the target DNA is believed to potentially affect a number of factors such as transcriptional status, association with histones and other DNA-binding proteins, and DNA bending. The authors performed a comprehensive computer analysis of the integration specificity of Drosophila melanogaster LTR-retrotransposons and retroviruses including an analysis of the nucleotide composition of targets, terminal sequences of LTRs, and integrase sequences. A classification of LTR-retrotransposons based on the integration specificity was developed. All the LTR-retrotransposons of the gypsy group with three open frames (errantiviruses) and their derivatives with two open frames demonstrate strict specificity to a target DNA selection. Such specificity correlates with the structural features of the target DNA: bendability, A-philicity, or protein-induced deformability. The remaining LTR-retrotransposons (copia and BEL groups, blastopia and 412 subgroups of the gypsy group) do not show specificity of integration. Chromodomain is present in the integrase structures of blastopia and 412 subgroup LTR-retrotransposons and may facilitate the process of non-specific integration.

Estrogen receptors, antiestrogens, and non-small cell lung cancer.

This review considers data on expression of different types of estrogen receptors (ERα and ERß) in in vitro cultured cells of non-small cell lung cancer and also in human and animal lung tumors. Estrogens are shown to play an important role in genesis and development of non-small cell lung cancer because the estrogen-stimulated cell proliferation as well as antiestrogen-caused inhibition of proliferation occurred only in the cells expressing different types of estrogen receptors. In general, the situation is similar to that observed in breast cancer, but in the cells of non-small cell lung cancer not ERα are expressed in more than half of cases but ERß. Just estrogen receptors ß play the crucial role in inducing cell proliferation in response to estrogens, and ERß is a prognostic marker of a favorable course of non-small cell lung cancer. Data on the interactions between ER and EGFR signaling pathways, as well as on the additive antitumor effect of antiestrogens (tamoxifen and fulvestrant) combined with tyrosine kinase inhibitors (gefitinib, erlotinib, and vandetanib) are considered. The review also includes data on the influence of estrogens on genesis and development of lung cancer in humans and animals and the frequency of ERα and ERß expression in non-small cell lung cancer in tissues from patients of the two sexes. Problems of quantitative determination of α and ß estrogen receptors in the tumor cells are also discussed.

[Analysis of the structure and expression of the cluster of Drosophila melanogaster genes DIP1, CG32500, CG32819, and CG14476 in the flamenco gene region].

The flamenco gene controlling transpositions of the gypsy retrovirus is localized in the 20A1-3 region, in which eight open reading frames organized in a cluster were discovered: DIP1, three repeats of CG32500 and CG32819, and CG14476. Analysis of the genes composing the cluster indicates that their transcription in Drosophila melanogaster is a stage-specific process. Comparison of the expression of these genes in the strains OreR, SS, and MS having the flamenco phenotype and in the strain 413 having the flamenco+ phenotype revealed differences only for the DIP1 gene, transcription of this gene being altered only in the OreR strain. Thus, mutant flamenco alleles are differently expressed in different strains. The structural organization of the flamenco gene region was studied in different Drosophila species: D. sechellia, D. simulans, D. mauritiana, D. yakuba, D. erecta, D. virilis, D. ananassae, D. grimshawi, and D. pseudoobscura. The genes of the cluster were found to be highly conserved in genomes of different species, but in none of them, except D. sechellia, the structural organization of the region repeats the structure of the D. melanogaster cluster.

[Molecular phylogeny and systematics of Drosophila retrotransposons and retroviruses].

Full classification of Drosophila melanogaster retrotransposons with long terminal repeats (LTR-retrotransposons) has been recomposed, and their evolutional analysis in sequenced genomes of different species of drosophila and other arthropods has been carried out. D. melanogaster LTR-retrotransposons are divided in three groups: gypsy (one, two or three open reading frames - ORFs), copia (one ORF), BEL (one ORF). Gypsy group is divided into three subgroups. Subgroup I is underrepresented by retrotransposons-retroviruses with three ORFs and their derivatives which have lost the env gene (ORF3). Subgroup II is underrepresented by retrotransposons with two ORFs, subgroup III - by retrotransposons with one ORF. Comparative analysis of homologs of gypsy group LTR-retrotransposons evidences that subgroups I and II are only in genomes of Lepidoptera and Diptera. Gypsy group of LTR-retrotransposons with one and two ORFs are found in almost all genomes of arthropods. Most of the families of D. melanogaster gypsy group LTR-retrotransposons have close homologs in genomes of other species of drosophila. A degree of identity of retrotransposons sequences is correlated with a degree of relation between species of drosophila; it's evidences about vertical transmission of retrotransposons. Obvious cases of horizontal transfer of some mobile elements have been detected including retrotransposons without the env gene. Homologs of distinct ORFs of retrotransposons - genes gag and env - have been found. Gene-homolog of the gag gene - Grp (CG4680) - is under purifying selection; so it has an important function in drosophila genome.

[Analysis of the structure and expression of the DIP1 gene in Drosophila melanogaster strains mutant for the flamenco gene].

DIP1 gene transcription was analyzed with the use of RT-PCR in three Drosophila melanogaster strains with the flamenco- phenotype (flam(SS), flam(MS), and flam(Ore)) and in one flamenco+ strain at the stages of embryos (0-24 h), third-instar larvae, and adult flies. The mutant strains flam(SS) and flam(Ore) lack an active copy of transposon gypsy. Theflam(MS) strain was obtained by introducing an active copy of gypsy in flies of theflam(SS) strain and is characterized by a high rate of gypsy transpositions. The experiments showed that at least five forms of DIP1 gene transcripts are produced. The form of cDNA corresponding to CDS DIP1-d was discovered only in embryos. It was found that DIP1 gene transcription depends on the age of flies: at the larval stage the level of transcription is significantly reduced. However, no reduction of gene transcription is observed in theflam(Ore) strain. These results suggest that the flamenco- phenotype may be associated with an alteration of DIP1 gene transcription, as in differentflamenco- strains the DIP1 gene expression is changed differently.

[Surgical treatment of Taussig-Bing anomaly in children in the first year of life].

The history of surgical treatment, clinical features, and main variants of correction of Taussig-Bing anomaly in children during the first year of life is briefly reviewed including original data obtained in the Department of Urgent Surgery of newborn and first-year infants, A. N. Bakulev Research Centre of Cardiovascular Surgery for the period of 2000-2006.

[Molecular evolution of mobile elements of the gypsy group: a homolog of the gag gene in Drosophila].

Retrotransposons of the gypsy group of Drosophila melanogaster that are structurally similar to retroviruses of vertebrates occupy an important place among retroelements of eukaryotes. The infectious abilities of some retrotransposons of this group (gypsy, ZAM, and Idefix) have been demonstrated experimentally, and therefore they are true retroviruses. It is supposed that retrotransposons can evolve acquiring new components, the sources of which remain to be elucidated. In this work, the CG4680 gene (Gag related protein, Grp) homologous to gag of retrotransposons of the gypsy group has been identified in the genome of D. melanogaster and characterized. The Grp gene product has a highly conserved structure in different species of the Drosophilidae family and is under of stabilizing selection, which suggests its important genomic function in Drosophila. In view of the earlier data, it can be concluded that homologous genes of all components of gypsy retrotransposons are present in the Drosophila genome. These genes can be both precursors and products of domestication of retrovirus genes.

[Results of bidirectional cavapulmonary shunt operation without cardiopulmonary bypass in children with complicated congenital heart defects during the first year of life].

The authors present results of bidirectional cavapulmonary shunt operation without cardiopulmonary bypass for the treatment of complicated congenital heart defects. Temporary blood shunting during surgical intervention enables cavapulmonary anastomosis to be created without making resort to artificial circulation (AC) and limitation on the time of superior vena cava occlusion. The proposed method is free from additional risks and excludes negative effects of AC. It allows for conversion to AC as appropriate at any time during surgery in the "bypass stand-by" regime.

[Evolution of errantiviruses of Drosophila melanogaster. Strategy 2: from retroviruses to retrotransposons].

Drosophila melanogaster retrotransposons of the gypsy group are considered to be potential errantiviruses. Their infectivity is caused by the functional activity of the third open reading frame (ORF3) encoding the Env protein, which was probably captured from baculoviruses. Mobile genetic elements (MGEs) of the gypsy group can be conventionally divided into three subgroups: with three ORFs, with a defective ORF3, and without the ORF3. To establish the patterns of evolution of gypsy retrotransposons in D. melanogaster, the members of the three subgroups were examined. Structural analysis of retrotransposons opus and rover, which carry a defective ORF3, as well as retrotransposons Burdock, McClintock, qbert, and HMS-Beagle, which lack the ORF3, suggests that the evolution of these MGEs followed the pattern of loosing the ORF3. At the same time, an MGE of the same subgroup, Transpac, may be an ancestral form, which had acquired the env gene and gave rise to the first errantiviruses. The capture of the ORF3 by retrotransposons provided their conversion to a fundamentally new state. However, the ORF3 in the genome is not subjected to strong selective pressure, because it is not essential for intragenomic transpositions. Because of this, the process of its gradual loss seems quite natural.