Variation of NimC1 expression in Drosophila stocks and transgenic strains.

The NimC1 molecule has been described as a phagocytosis receptor, and is being used as a marker for professional phagocytes, the plasmatocytes, in Drosophila melanogaster. In studies including tumor-biology, developmental biology, and cell mediated immunity, monoclonal antibodies (P1a and P1b) to the NimC1 antigen are used. As we observed that these antibodies did not react with plasmatocytes of several strains and genetic combinations, a molecular analysis was performed on the structure of the nimC1 gene. In these strains we found 2 deletions and an insertion within the nimC1 gene, which may result in the production of a truncated NimC1 protein. The NimC1 positivity was regained by recombining the mutation with a wild-type allele or by using nimC1 mutant lines under heterozygous conditions. By means of these procedures or using the recombined stock, NimC1 can be used as a marker for phagocytic cells in the majority of the possible genetic backgrounds

Definition of Drosophila hemocyte subsets by cell-type specific antigens.

We analyzed the heterogeneity of Drosophila hemocytes on the basis of the expression of cell-type specific antigens. The antigens characterize distinct subsets which partially overlap with those defined by morphological criteria. On the basis of the expression or the lack of expression of blood cell antigens the following hemocyte populations have been defined: crystal cells, plasmatocytes, lamellocytes and precursor cells. The expression of the antigens and thus the different cell types are developmentally regulated. The hemocytes are arranged in four main compartments: the circulating blood cells, the sessile tissue, the lymph glands and the posterior hematopoietic tissue. Each hemocyte compartment has a specific and characteristic composition of the various cell types. The described markers represent the first successful attempt to define hemocyte lineages by immunological markers in Drosophila and help to define morphologically, functionally, spatially and developmentally distinct subsets of hemocytes

The Repo homeodomain transcription factor suppresses hematopoiesis in Drosophila and preserves the glial fate

Despite their different origins, Drosophila glia and hemocytes are related cell populations that provide an immune function. Drosophila hemocytes patrol the body cavity and act as macrophages outside the nervous system whereas glia originate from the neuroepithelium and provide the scavenger population of the nervous system. Drosophila glia are hence the functional orthologs of vertebrate microglia, even though the latter are cells of immune origin that subsequently move into the brain during development. Interestingly, the Drosophila immune cells within (glia) and outside the nervous system (hemocytes) require the same transcription factor Glide/Gcm for their development. This raises the issue of how do glia specifically differentiate in the nervous system and hemocytes in the procephalic mesoderm. The Repo homeodomain transcription factor and pan-glial direct target of Glide/Gcm is known to ensure glial terminal differentiation. Here we show that Repo also takes center stage in the process that discriminates between glia and hemocytes. First, Repo expression is repressed in the hemocyte anlagen by mesoderm-specific factors. Second, Repo ectopic activation in the procephalic mesoderm is sufficient to repress the expression of hemocyte-specific genes. Third, the lack of Repo triggers the expression of hemocyte markers in glia. Thus, a complex network of tissue-specific cues biases the potential of Glide/Gcm. These data allow us to revise the concept of fate determinants and help us understand the bases of cell specification. Both sexes were analyzed.SIGNIFICANCE STATEMENTDistinct cell types often require the same pioneer transcription factor, raising the issue of how does one factor trigger different fates. In Drosophila, glia and hemocytes provide a scavenger activity within and outside the nervous system, respectively. While they both require the Glide/Gcm transcription factor, glia originate from the ectoderm, hemocytes from the mesoderm. Here we show that tissue-specific factors inhibit the gliogenic potential of Glide/Gcm in the mesoderm by repressing the expression of the homeodomain protein Repo, a major glial-specific target of Glide/Gcm. Repo expression in turn inhibits the expression of hemocyte-specific genes in the nervous system. These cell-specific networks secure the establishment of the glial fate only in the nervous system and allow cell diversification

A Drosophila melanogaster sejt-közvetítette immunitása = The cell mediated immunity of Drosophila melanogaster

A Projekt keretében a.) a vérsejtmarker panelt in vivo lamellocita markerrel egészítettük ki. b.) a Trol molekulát, az apoptotikus sejteket felismerő receptorként definiáltuk. c.) jellemeztük az immunkompartmentumok funkcióit és meghatároztuk a sejtes elemek eredetét. A vérsejtképző kompartmentumok az embrióban és a lárvában egymástól elhatároltak, míg az immunválasz során valamennyi kompartmentum részt vesz a vérsejtek képzésében. A lamellociták fejlődése több lépésben zajlik a szesszilis szövet kezdeti és fő részvételével. A lamellociták plazmatocita jellegű sejtekből képződnek ezért igazoltnak látjuk, hogy a fagocita sejtek nem terminálisan differenciálódott sejtek, hanem immunindukciót követően lamellocitákká alakulhatnak, mely nagyfokú plaszticitásukat mutatja. d.) immun-modulként jellemezhető génklasztert azonosítottunk Drosophilában és egyéb rovarfajokban. A génklaszter egyes tagjai részt vesznek a mikróbák opszonizálásában, sejthez kötésében és a fagocitózis folyamatában. e.) a sejt közvetítette immunitás eddig ismeretlen formáját találtuk és jellemeztük egyes Drosophila fajokban. A tokképző reakcióban sokmagvú óriássejtek vesznek részt, melyek a gerinces szervezetek egyes granulómáira jellemző óriássejtekhez hasonlítanak. f.) veleszületett immunitás témájú kurzusokat tartottunk és szakdolgozókat valamint Ph.D. hallgatókat foglalkoztatunk a laboratóriumban. | In the framework of the Project we: a.) expanded the hemocyte marker panel with an in vivo lamellocyte marker. b.) defined Trol as a receptor molecule for apoptotic cells on plasmatocytes. c.) characterized the cellular elements of the immune compartments with respect to function and origin. The hematopoietic compartments are separated during the embryonic and larval development however, in the course of the cell mediated immune response all compartments contribute to the development of effector cells. The differentiation of lamellocytes occurs in sequence with the initial and major contribution of the sessile hematopoietic tissue. The lamellocytes differentiate from precursors with the characteristics of plasmatocytes therefore it is proposed that phagocytic cells are not terminally differentiated cells but upon immune stimulation they may become lamellocytes, illustrating their striking plasticity. d.) identified a gene cluster instrumental in cell mediated immunity in Drosophila and in insects, in general. The members of the gene cluster encode proteins apparently involved in binding, opsonization, and phagocytosis of bacteria. e.) found a novel form of the cell mediated immunity of Drosophila species. The encapsulation reaction involves the contribution of multinucleated giant hemocytes resembling to multinuclear giant cells in granuloma formation in vertebrates. f.) ran courses in innate immunity and trained undergraduate and graduate students in the laboratory

A Drosophila melanogaster sejtes immunitása = The cellular immunity of Drosophila melanogaster

A Drosophila sejtközvetítette immunválaszának szabályozását vizsgáltuk valamint molekuláris immunológiai és genetikai ismeretek elsajátítását és projekt építését tettük lehetővé a tudomány iránt érdeklődő diákok és kutatók számára.Adult Drosophila vérsejtjeire, makrofágokra és a lamellocitákra jellemző markereket azonosítottunk.Az L5 antigén a lamellociták differenciálódásának a szuppresszora.A P1 antigénről (Nimród) megállapítottuk, hogy részt vesz a fagocitózisban.A P1 molekula jellegzetes motívumot hordoz (Nim-repeat),mely egy szupercsaládot határoz meg:tagjai a kódoló gén közvetlen környezetében helyezkednek el. Javaslatot tettünk a Nim repeat kialakulásának a modelljére,leírtuk a Nimród szuprcsalád lehetséges evolúcióját.A vérképzést és a vérsejtek funkcióit szabályozó géneket és molekulákat azonosítottunk.Egy epigenetikus regulátorról megállapítottuk,hogy a vérsejtek osztódását,egy mestergénről pedig,hogy a lamellociták differenciálódását szabályozza.RNSi mutánsgyűjteményben a szesszilis szövet kialakulásában résztvevő génterméket azonosítottunk.Megállapítottuk, hogy a lamellociták a szesszilis szövetből származnak,effektorsejtekké történő differenciálódásuk lépései immunológiai markerekkel nyomonkövethetők.Eddig nem ismert sejteket találtunk Drosophila fajokban és a jellemzésükre alkalmas immunológiai markereket azonosítottunk.Az általunk felismert markereket a Drosophila vérsejt-differenciálódását és funkcióit vizsgáló laboratóriumokban rutinszerűen használják. | We studied the regulation cellular immunity of Drosophila and developed a training-unit based on the research and teaching experience of our multidisciplinary team, with a broad interest in molecular immunology. Results: We identified markers for embryonic macrophages, lamellocytes and blood cells of the adult fly. We described the L5 antigen as a suppressor of lamellocyte development. We defined P1 antigen (Nimrod) as a phagocytosis receptor with a structurally and phylogenetically conserved characteristic unit, the Nim repeat. The repeat defines a superfamily with members located in the close proximity of the p1 gene. We suggested a model for the origin of the Nim repeat, and described the possible evolution of the superfamily. We defined an epigenetic regulator of blood cell differentiation and a master gene regulating the development of lamellocytes. We defined the sessile hematopoietic tissue as the source of lamellocytee precursors. We characterized sequential events in lamellocyte development from sessile stem cells to mature lamellocytes by sequential expression of lamellocyte antigens. We found so far undefined cell types in Drosophila species and developed immunological markers for them. The hemocyte markers defined in our laboratory are used worldwide routinely in studies of blood cell development and function in Drosophila

Genes encoding cuticular proteins are components of the Nimrod gene cluster in Drosophila.

The Nimrod gene cluster, located on the second chromosome of Drosophila melanogaster, is the largest synthenic unit of the Drosophila genome. Nimrod genes show blood cell specific expression and code for phagocytosis receptors that play a major role in fruit fly innate immune functions. We previously identified three homologous genes (vajk-1, vajk-2 and vajk-3) located within the Nimrod cluster, which are unrelated to the Nimrod genes, but are homologous to a fourth gene (vajk-4) located outside the cluster. Here we show that, unlike the Nimrod candidates, the Vajk proteins are expressed in cuticular structures of the late embryo and the late pupa, indicating that they contribute to cuticular barrier functions

Emblemata, et aliquot nummi antiqui operis, Ioan. Sambuci Tirnaviensis Pannonii.

Sig. A-Q8, R7, S8Grav. xil orlats. - Les p. 241-256 (quadern R), intercalades entre la 256 i la 257, son grav. xil. de medalles. - Ornaments tip. - Capital gravReclam

A novel method for the identification of factors involved in host-pathogen interactions in Drosophila melanogaster.

A new method was established, standardized and validated for screening factors involved in the response to septic injury in Drosophila melanogaster. The method, based on inducing lesion by removing the tarsal segments of the first pair of legs of Drosophila adults and exposing them to different bacteria, imitates injury that often occurs in the natural habitat. The method is easy to perform, highly reproducible and suitable for large-scale genetic screens with the aim of identifying factors involved in host-pathogen interactions. The technique was validated by using mutant variations of different components of the immune response, blood clotting as well as the involvement of a number of genes known to be instrumental in the humoral and cell-mediated immune responses of Drosophila was confirmed. Moreover, the combination of the present method with antibiotic treatment allows the screening of potential antimicrobial drugs in vivo