The RNA-Binding Protein SBR (Dm NXF1) Is Required for the Constitution of Medulla Boundaries in Optic Lobes.

() is an orthologue of the () genes in different The known function of genes is the export of various mRNAs from the nucleus to the cytoplasm. The cytoplasmic localization of the SBR protein indicates that the nuclear export function is not the only function of this gene in RNA-binding protein SBR enriches the nucleus and cytoplasm of specific neurons and glial cells. In mutant males, the disturbance of medulla boundaries correlates with the defects of photoreceptor axons pathfinding, axon bundle individualization, and developmental neurodegeneration.

Psychological and social impact of COVID-19.

The high numbers of COVID-19 infections and deaths, economic difficulties, uncertainty about the future, as well as the approaches needed to contain the spread of the virus are all playing critical roles in the short and long-term social and psychological impact of the COVID-19 pandemic. Inequities based on race and socioeconomic status influence the rates of infection and deaths and steps that are needed to achieve recovery. This commentary focuses on similarities and differences after other disasters and efforts being initiated to provide support and recovery.

Dynamic maternal gradients and morphogenetic networks in Drosophila early embryo.

Here, we review the latest publications on dynamics and interpretation of morphogen gradients in Drosophila early embryo. The instructive cues provided by these gradients are further interpreted by target genes to enable correct cell fate specification. Moreover, recent studies point on the dynamic and active input from gradients themselves.

RNA-binding proteins of the NXF (nuclear export factor) family and their connection with the cytoskeleton.

The mutual relationship between mRNA and the cytoskeleton can be seen from two points of view. On the one hand, the cytoskeleton is necessary for mRNA trafficking and anchoring to subcellular domains. On the other hand, cytoskeletal growth and rearrangement require the translation of mRNAs that are connected to the cytoskeleton.

Cytoplasmic localization of SBR (Dm NXF1) protein and its zonal distribution in the ganglia of Drosophila melanogaster larvae.

The Drosophila gene Dm nxf1 (nuclear export factor 1) previously known as small bristles (sbr) controls nuclear export of various mRNA transcripts. We found that Dm NXF1 is present not only in nucleoplasm or at the nuclear rim but also in the cytoplasm. On the spatiotemporal level, anti-SBR antibodies labeled some neuroblasts and their lineages in the brains of Drosophila larvae.

[Morphogenetic Networks which Determine the Spatial Expression of Zygotic Genes in Early Drosophila Embryo].

This review deals with the recent studies expanding the idea of positional information in the early embryogenesis of Drosophila melanogaster. Previous studies showed that, in the course of segment determination in Drosophila, information created by gradients of products of maternal coordinate genes is not “read” statically, being interpreted by their zygotic target genes via regulatory interactions. This leads to spatial shifts in the expression of target genes relative to the original positions as well as to dynamic reduction in the zygotic expression variability.

Testis-specific products of the Drosophila melanogaster sbr gene, encoding nuclear export factor 1, are necessary for male fertility.

The evolutionarily conserved nuclear export factor 1 (NXF1) provides mRNA export from the nucleus to the cytoplasm. We described several testis-specific transcripts of the Drosophila melanogaster nxf1 gene designated “sbr” in this species via different PCR approaches and CAGE-seq analysis. Characteristically, most of them have truncated 3′UTRs compared with those in other organs.

[THE ROLE OF sbr/Dm nxf1 GENE DURING SYNCYTIAL PERIODS OF DEVELOPMENT IN DROSOPHILA MELANOGASTER].

The syncytial development is a feature of early embryogenesis and spermatogenesis in Drosophila melanogaster. All elements of syncytium are interconnected by single cytoskeletal network that enables equal conditions and provides synchronic development. The cytoskeleton is essential for the formation and functioning of the mitotic spindle, cytoskeletal elements are the main structural component of cilia and flagella.

Quantitative dynamics and increased variability of segmentation gene expression in the Drosophila Krüppel and knirps mutants.

Here we characterize the response of the Drosophila segmentation system to mutations in two gap genes, Kr and kni, in the form of single or double homozygotes and single heterozygotes. Segmentation gene expression in these genotypes was quantitatively monitored with cellular resolution in space and 6.5 to 13min resolution in time.

[Spermatogenesis in Drosophila melanogaster: the role of the basic transport receptor of the mRNA (Dm NXF1)].

Specificity of regulation of genes expression at the transcriptional and posttranscriptional levels is typical for spermatogenesis in Drosophila and mammals, including humans. It becomes apparent in the existence of testis specific NXF (nuclear export factor). We have shown that the Dm NXF1 (SBR) protein is present in considerable amounts at all stages of the spermatogenesis.

Alternative transcripts expressed by small bristles, the Drosophila melanogaster nxf1 gene.

The tissue-specific accumulation of small bristles (Dm nxf1) transcripts at different developmental stages of Drosophila melanogaster was analyzed by Northern blots and RT PCR. We identified four distinct transcripts: ubiquitous (3.5kb); ovary and early embryo specific (3.

Dm nxf1/sbr gene affects the formation of meiotic spindle in female Drosophila melanogaster.

The small bristles (sbr) gene of Drosophila melanogaster belongs to the family of nuclear export factor (NXF) genes that participate in mRNA nuclear export. During meiosis, females of Drosophila melanogaster that carry various combinations of mutant alleles of the Dm nxf1/sbr gene exhibit disruption of the division spindle and misalignment of chromosomes at the metaphase plate. Meiosis of sbr ( 5 ) /+ females is characterized by the formation of tripolar spindles during the first cell division.

[Centrosome as "a brain" of an animal cell].

Centrosomes are the major centre of microtubule nucleation and microtubule minus-ends concentration in animal cells. Microtubule plus-ends are directed to a nucleus and chromosomes or to a cell cortex. The crossing of signal transduction pathways and the network of interactions between signal molecules controlling cell cycle are revealed in centrosomes.

[Hyperthermia of male Drosophila melanogaster meiocytes induces abnormalities in both paternal and maternal sex chromosome sets of the offspring].

Nondisjunction and loss of sex chromosomes caused by exposure of male Drosophila melanogaster to heat shock (HS) (37 degrees C for 1 h) has been studied to determine the role of mutation l(1)ts403 (sbr10) in the control of chromosome segregation during cell division. Hyperthermia of males at the pupal stage has been demonstrated to increase the number of offspring with abnormalities of not only paternal, but also maternal sex chromosome sets. According to the criterion used, there is a temperature-sensitive period of spermatogenesis, which presumably coincides with meiosis.

[Genetic nature of abnormal larval development in the progeny of l(1)ts403(sbr10) females of Drosophila melanogaster].

In Drosophila melanogaster the small bristles (sbr) gene is vital and evolutionary conservative and controls nuclear export of mRNA. Sbr mutant alleles had a broad pleiotropic effect. High frequency of abnormal larva dying (up to 18 %) at the first instar stage in progeny of heat shock (37 degrees C, 1 h) treated mutant females is one of the most interesting l(l)ts403(sbr10) allele effects.

[The relationship between nuclear-cytoplasmic transport and chromosome segregation].

Chromosomes/chromatids transport to cell division poles (chromosome segregation) and nuclear-cytoplasmic transport give way to each other during cell cycle. Disassembly and reassembly of the nuclear envelope during input or output mitosis are the critical time periods for changing one kind of transport system for the other one. The interest in the problem of relationships between nuclear-cytoplasmic transport and chromosome segregation came into view after revealing some factors involved in both transport systems.

[Sterilizing effect of the mutant allele sbr10 (l(1)ts403) in compound with null alleles in Drosophila melanogaster females].

In females of Df(1)v-L4/+(0/+) genotype, the presence of the wild-type allele of small bristles (sbr) gene in a single dose has no significant effect on their fecundity, whereas a reduced dose of the temperature-sensitive allele sbr10(l(1)ts403) causes a strong sterilizing effect in females Df(1)v-L4/sbr10 (0/sbr10) at permissive temperature. We studied the contribution to this effects of the following factors: resorption of egg chambers, decreased oviposition, offspring death at the embryonic and larval stages, and reduced fecundity in females 0/sbr10. Sterilizing effect of the mutant sbr10 allele proved to be primarily caused by offspring lethality at the embryonic and first-instar larval stages.

[Genetic control of development of the Malpighian vessels in Drosophila melanogaster].

Malpighian tubules of insects are a functional analog of mammalian kidneys and serve as a classical model for studying the structure and functions of transport epithelium. The review contains the data on structural organization, functioning, and formation of the Malpighian tubules during embryogenesis in Drosophila melanogaster. Various systems of genes are described that control the program of development of the renal (Malpighian) tubules in D.

[Semidominant effect of the l(1)ts403 (sbr10) mutation on nondisjunction of sex chromosomes in meiosis in Drosophila melanogaster females exposed to heat].

The sbr gene of Drosophila melanogaster belongs to the NXF (nuclear export factor) family responsible for the mRNA transport from nucleus to cytoplasm. We have shown that in the heat-exposed (37 degrees C, 1 h) females, the l(1)ts403 (sbr10) mutation leads, in particular, to the high-frequency nondisjunction and loss of sex chromosomes in meiosis. For this trait, the incomplete dominance of the sbr10 mutation is observed.

[The sbr gene product in Drosophila melanogaster and its orthologs in yeast (Mex67p) and human (TAP)].

A DNA sequence from the 9F region of Drosophila melanogaster polytene chromosomes was cloned. Sequencing the cloned region and its comparison with the known sequences of the D. melanogaster genome showed that the cloned DNA part contains gene sbr and adjacent sequences.

[Maternal and paternal effects on the specific mutation l(1)ts403 of thermosensitivity of early Drosophila melanogaster embryos].

High thermosensitivity of early embryos controlled by mutation l(1)ts403 with disturbed heat-shock response was studied. Thermosensitivity was examined in early (0-1 h) and late (3.5-4.

[Development of thermotolerance in Drosophila melanogaster line l(1) ts403 with a defect in heat shock protein synthesis].

To elucidate the role of heat shock proteins (HSP) in the formation of resistance to extreme factors and in the development of organismic and cell response to these factors, thermotolerance in a Drosophila melanogaster line with defective HSP synthesis was studied with regard to several criteria: (1) survival of adult-females; (2) damage to egg chambers in ovarioles; (3) dynamics of oviposition; (4) frequency of loss and nondisjunction of sex chromosomes in meiosis of females exposed to a heat shock (HS). According to all these criteria, the l(l)ts403 females were more sensitive to a HS 37 degrees C, the exposure at 37 degrees C for 1 h (HS37) than the females of the wild-type line Canton S. Only the data on the first three aforementioned parameters were indicative of thermotolerance development.

[Consequences of exposure to extreme conditions in somatic cells of Drosophila melanogaster under conditions of disturbed synthesis of heat shock proteins].

Restoration of cell proliferation and repair of chromosome damage (chromatin agglutination, pulverization, or aggregation) in conditions of disturbed synthesis of heat shock proteins (HSPs) was studied in nerve ganglia of Drosophila melanogaster larvae. Two approaches were used to suppress the heat shock response: (1) anaerobic heating of wild-type Canton S larvae at 37 degrees C for 13 min, which temporarily blocked HSP gene expression at the transcriptional level [1], and (2) aerobic heating of mutant l(1)ts403 larvae at 37 degrees C for 30 min, which disturbed HSP gene expression at the posttranscriptional level [2]. The duration of heat treatment was selected according to the period of regression of heat shock puffs [3].

[The regression time of heat-shock puffs in the polytene chromosomes of Drosophila melanogaster as a criterion for assessing the effect of different stress exposures].

The time of regression of heat shock puffs was studied in the polytene chromosomes of Drosophila melanogaster larvae of mutant stock (1(1)ts403, defective in heat shock protein (HSP) system, and of the wild type stock Canton S after heat shock (37 degrees C), after placing of larvae to anaerobic conditions (dipping into physiological solution), and after combination of these treatments. It is shown that the time of regression of heat shock puffs depends on the specificity of the treatment (heat shock or anaerobic conditions), its duration (13 or 30 min), or on the peculiarity of functioning of HSP system in the cells of different stock larvae. Our results are in accordance with the idea of the HSP genes expression autoregulation, and allow to use the heat shock puff regression time as a criterion for estimation of damaging effects of stress factors.

[Mechanisms ensuring the resistance of the genetic material of the cell to stress exposures].

A brief review of studies performed in the Department of Genetics of St. Petersburg University by M.E.