[Cytophotometric determination of genome size in two species of Cyclops Lake Baikal (Crustacea: Copepoda: Cyclopoina) in ontogenetic development].

Genome size of Cyclops in cells at early stages of cleavage (up to the 5th division) and in somatic cells were estimated by a static digital Feulgen cytophotometry in order to study the quantitative changes in DNA content during chromatin diminution. Our realization of the cytophotometric method was approbeted on five different digital-imaging systems in blood cells of four vertebrate species. In all cases, we observed a direct correlation of the obtained and known from the literature data on the genome size and a high reproducibility, which allows to use these systems in future work.

[Drosophila melanogaster imaginal discs mitotic anomalies induced by tumor-supressor dlg silencing construction].

Mitosis, cytokinesis and nuclear texture of wing imaginal discs cells silenced by UAS-RNAi-dlg construct induced by 1096-Ga 14 driver were studied. The silencing construct contains coding region of dlg gene and the complementary region. Further, this RNA hairpin (Dietzl et al.

[Role of the Drosophila melanogaster hrs gene in wing formation].

The Hrs (hepatocyte growth factor receptor tyrosine kinase substrate) protein is an endosomal protein whose function is to transport receptor tyrosine kinases from early endosomes to lysosomes. Since receptor tyrosine kinases are involved in various signaling pathways, HSR defects lead to various malformations. A study of the role of the hrs gene in wing development in Drosophila confirmed that the gene is involved in the formation of the D/V boundary of the wing imaginal disk and suggested a new role in wing vein refinement for the gene.

[Nucleus DNA content measurement methods features].

We suggest a new theoretical method of the flow cytometry DNA histograms and apply it for Drosophila melanogaster imaginal discs cells. The model gives a possibility to determine the proportions of cells in G1, G2 (M) and S cell cycle phases. We show that the precision of G1 and G2 (M) DNA content measurements is limited by the precision of device zero signal arrangement.

[Nuclear texture in mitotic cells].

Changes of nuclear texture in mitotic cells of Drosophila melanogaster imaginal discs were studied. The distribution of voxels DAPI fluorescence intensities was used as the quantitative measure of the nuclear texture. The integral characteristics such as the portion of voxels with a given fluorescent signal level and autocorrelation of pixel intensities were used.

[The influence of morphogene Wg on the formation of an ectopic eye in Drosophila melanogaster].

Due to the ectopic expression of the ey gene in the wing imaginal disc under the action of the 1096-Gal4 driver, a part of the wing disc cells change their fate and become eye cells. Ectopic eyes are induced in definite regions of the wing disc and form a stable pattern on the wing of an adult fly. Here, we have shown that the ectopic expression of Wg inhibits the formation of ectopic eyes, and conversely the expression of Wg is reduced in the sites of ectopic Ey expression.

[Duration of the cell cycle phases in mutants for the tumor suppressor Merlin in Drosophila melanogaster].

The cell cycle duration was estimated in Drosophila melanogaster mutants for the tumor suppressor Merlin with the use of different approaches. Experiments on induction of mosaic clones in tissues of the larval wing imaginal disc showed that the cell cycle in mutant discs is shorter than that in control. Flow fluorescence cytometry revealed no differences between mutant and normal animals in the relative duration of the cell cycle phases, which suggests proportional shortening of the cell cycle phases.

[DNA contents in nuclei of Cyclops kolensis and C. insignis (Crustacea, Copepoda)].

Chromatin diminution (CD) in two Cyclopoida species, Cyclops kolensis and C. insignis, was studied by static digital Feulgen cytophotometry. DNA content (pg/cell) was evaluated by standard curves builded up using blood cells of five organisms with known DNA content, which ranged from 1.

[Fluorometric identification of chromatin packing level laying out of the light microscopy resolution].

Confocal microscopy permits to perform quantitative analysis of the fluorescent signals of the nuclei. We determined the level of DAPI and phosphorylated histone-H3 fluorescence, the volume of DAPI and phosphorylated histone-H3 fluorescence in normal (Hikone AW) and colchicine treated third instar Drosophila melanogaster wing imaginal disc mitotic cells. Our analysis permitted to indentify two unknown levels of chromatin package; one in the prometaphase and another at the end of metaphase.

[Study of the functional role of mutation in the guinea pig-adapted Ebola virus genome on a Drosophila melanogaster model].

Ebola virus virulence in guinea pigs, which appears through virus adaptation to this animal host, correlates with substitutions in the gene encoding vp24 protein. In particular, the substitution His-->Tyr186 was found when obtaining strain 8 ms. An attempt was made to clarify the functional role of this substitution in a transgenic fruit fly model.

[The role of the functional sites of the Merlin tumor suppressor in Drosophila spermatogenesis].

The Merlin gene of Drosophila is homologous to the human Neurofibromatosis 2 (NF2) gene an important regulator of proliferation and endocytosis of cell receptors. It was earlier shown that the Thr5 residue of the Drosophila Merlin protein was homologous to Ser518 of the human protein (which was already known to undergo phosphorylation); hence, it was assumed that Thr559 of Drosophila also was a substrate of phosphorylation. The mutant Merlin proteins MerT559D (an analog of the phosphorylated form) and MerT559A (a nonphosphorylated form) were constructed and tested, under the conditions of ectopic expression for the ability to correct the spermatogenesis defects induced by the Mer4 mutation.

[An intergral method for quantitative cell DNA content measurements by digital microphotography].

Quantitative nuclei DNA content measurement based on Feulgen reaction and the analysis of CCD images was tested. The measurements were performed in monochorome CCD option (650 X 514 pixels) with the wavelength 551 nm. The linear dependence of photomatrix elements signals on the falling light was shown with the use of multigraded light absorption filter.

[Drosophila melanogaster gene Merlin interacts with the clathrin adaptor protein gene lap].

The protein Merlin is involved in the regulation of cell proliferation and differentiation in the eyes and wings of Drosophila and is a homolog of the human protein encoded by the Neurofibromatosis 2 (NF2) gene whose mutations cause auricular nerve tumors. Recent studies show that Merlin and Expanded cooperatively regulate the recycling of membrane receptors, such as the epidermal growth factor receptor (EGFR). By performing a search for potential genetic interactions between Merlin (Mer) and the genes important for vesicular trafficking, we found that ectopic expression in the wing pouch of the clathrin adapter protein Lap involved in clathrin-mediated receptor endocytosis resulted in the formation of extra vein materials.

[Effect of mutations in Drosophila melanogaster tumor suppressor Merlin on proliferation and differentiation of wing cells].

Experiments on transplantation of wing imaginal discs homozygous for a mutation in the tumor suppressor gene Merlin have demonstrated that this mutation does not induce malignant tumors. Marking of the wing disc compartment borders by specific antibodies showed the absence of essential compartment border defects in case of the Merlin mutation. Drosophila melanogaster cells mutant for Merlin have shorter cell cycle than normal cells.

[Dynamics of the spatial organization of the chromosome set in cells of Drosophila melanogaster imaginal disks normally and under the action of the tumor-inducing mutation Merlin].

Fluorescence of H3-p histone and DAPI was studied at different stages of interphase and mitosis in cells of imaginal disks of third-instar Drosophila melanogaster larvae. Three stages differing in the spatial organization of the chromosome set in mitosis were revealed. At the first stage (prophase, prometaphase), the histone 3 phosphorylation level rises, and the volume occupied by the chromosome set in the nucleus increases.

[High frequency induction of small mosaic cell clones in the Drosophila wings under the influence of gamma-irradiation].

As it was shown earlier in Gonzalez-Gaitan et al., one-cell and two-cells clones (tailing clones) are induced in the Drosophila wings after irradiation and represent a significant portion of clones detected with the use of mwh genetic marker. Our experiments shown that gamma-irradiation occur to be more efficient inductor of such small clones.

[Role of the porcupine gene in the development of the wing imaginal disk of Drosophila melanogaster].

A search for the genes interacting with the Merlin tumor suppressor gene revealed a Merlin-porcupine interaction during wing morphogenesis. Ectopic expression of the porcupine gene in the wing imaginal disk reduced the adult wing, while addition of an UAS construct with a full-length or truncated copy of the Merlin gene partly restored the wing phenotype. The highest restoration level was observed upon adding the fragments coding for the C end of the Merlin protein.

[The role of Gilgamesh protein kinase in Drosophila melanogaster spermatogenesis].

The cellular function of the gilgamesh mutation (89B9-12) of casein kinase gene in Drosophila spermatogenesis was studied. It was demonstrated that the sterility resulting from this mutation is connected with the abnormalities in spermatid individualization. A phylogenetic study of the protein sequences of casein kinases 1 from various organisms was conducted.

[Specifics of anaphase chromatid disjunction in Drosophila melanogaster mitotic mutants].

Anaphase chromatid behavior defects (CBDs) were quantitatively and qualitatively studied in nerve ganglion cells of third-instar larvae of several control wild-type Drosophila melanogaster strains and four strains with mutations of the aar(v158), ff3, mast(v40), and CycB(2g) cell-cycle genes. A linear specificity was observed for the CBD frequency, type, determination, and correction probability. The probability of anaphase CBD correction was close to unity in the control strains and lower in the mutant strains.

[Chromosome nondisjunction in Drosophila strains mutant for tumor suppressor Merlin].

The effect of mutation for gene Merlin on chromosome disjunction in Drosophila during meiosis was genetically studied. Chromosome nondisjunction was not registered in females heterozygous for this mutation and containing structurally normal X chromosomes. In cases when these females additionally contained inversion in one of chromosomes X, a tendency toward the appearance of nondisjunction events was observed in individuals containing mutation in the heterozygote.

[The distribution of mitoses in the imaginal disks of third-instar Drosophila melanogaster larvae].

Development of Drosophila imaginal discs is accompanied by a high-ordered cell proliferation. However, the distinctions in the topographic distribution of mitoses at different developmental stages are insufficiently studied. In this work, we have analyzed the distribution of mitoses in the wing disc of third-instar larvae and determined the regions where mitotic clustering.

[A method for transformation of Drosophila germline cells with a high-concentration exogenous DNA].

A method for transformation of Drosophila germline cells without DNA capillary injections is proposed. The method involves a microneedle puncture of embryos and can be realized using simple equipment.

[Range of potential functions of the Drosophila melanogaster hdc gene].

The Drosophila melanogaster hdc gene controls trachea branching, which starts during embryo development. Expression in imaginal disks and reproductive organs suggests additional functions for the hdc gene. The gene was demonstrated to have a maternal effect, which was denied previously.

[Mitosis: regulation and organization of cell division].

Modern views on genetic, cytological and molecular bases of the structure and regulation of preparing and implementing mitotic chromosome segregation are discussed.

[Mutation of Indy(p115) increases the life expectancy of imago of Drosophila melanogaster depending on sex and genetic background].

The Indyp115 allele in heterozygous state almost doubles the life span of adult Drosophila melanogaster, and this effect largely depends on the strain used for obtaining heterozygotes. Male and female life span depends on Indyp115 to a different degree. Apart from Indyp115 heterozygotes, sexual dimorphism for life span was also observed in strain Hikone-AW, but not in OregonR and TM3 balancer.