Haemocyte changes in resistant and susceptible strains of D. melanogaster caused by virulent and avirulent strains of the parasitic wasp Leptopilina boulardi

Russo, Jacqueline; Brehélin, Michel; Carton, Y.

doi:10.1016/s0022-1910(00)00102-5

Cited by 95 publications

(78 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Soon after parasitization, circulating hemocyte concenCactus. Cactus is an IB-family protein and sequesters the Rel-family transcription Dorsal in the cytoplasm in tration of the host increases (Russo et al 2001). After a parasitized host molts into third instar, the lymph the absence of the Toll signal.…”

Section: Ellular Immune Responses In Higher Eukaryotesmentioning

confidence: 99%

Genetic Analysis of Contributions of Dorsal Group and JAK-Stat92E Pathway Genes to Larval Hemocyte Concentration and the Egg Encapsulation Response in Drosophila

2004

View full text Add to dashboard Cite

Drosophila larvae defend themselves against parasitoid wasps by completely surrounding the egg with layers of specialized hemocytes called lamellocytes. Similar capsules of lamellocytes, called melanotic capsules, are also formed around "self" tissues in larvae carrying gain-of-function mutations in Toll and hopscotch. Constitutive differentiation of lamellocytes in larvae carrying these mutations is accompanied by high concentrations of plasmatocytes, the major hemocyte class in uninfected control larvae. The relative contributions of hemocyte concentration vs. lamellocyte differentiation to wasp egg encapsulation are not known. To address this question, we used Leptopilina boulardi to infect more than a dozen strains of host larvae harboring a wide range of hemocyte densities. We report a significant correlation between hemocyte concentration and encapsulation capacity among wild-type larvae and larvae heterozygous for mutations in the Hopscotch-Stat92E and Toll-Dorsal pathways. Larvae carrying loss-of-function mutations in Hopscotch, Stat92E, or dorsal group genes exhibit significant reduction in encapsulation capacity. Larvae carrying loss-of-function mutations in dorsal group genes (including Toll and tube) have reduced hemocyte concentrations, whereas larvae deficient in Hopscotch-Stat92E signaling do not. Surprisingly, unlike hopscotch mutants, Toll and tube mutants are not compromised in their ability to generate lamellocytes. Our results suggest that circulating hemocyte concentration and lamellocyte differentiation constitute two distinct physiological requirements of wasp egg encapsulation and Toll and Hopscotch proteins serve distinct roles in this process.

show abstract

Section: Ellular Immune Responses In Higher Eukaryotesmentioning

confidence: 99%

Genetic Analysis of Contributions of Dorsal Group and JAK-Stat92E Pathway Genes to Larval Hemocyte Concentration and the Egg Encapsulation Response in Drosophila

2004

View full text Add to dashboard Cite

show abstract

“…The total number of hemocytes increases in parasitized larvae, and a specialized class of hemocytes, the lamellocytes, appears en masse (5,9). In a successful response, the lamellocytes form a melanized capsule around the parasite, which is eventually killed.…”

mentioning

confidence: 99%

A directed screen for genes involved in Drosophila blood cell activation

Zettervall

Ines

Williams

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

324

400

View full text Add to dashboard Cite

An attack by a parasitic wasp activates a vigorous cellular immune response in Drosophila larvae. This response is manifested by an increased number of circulating cells, the hemocytes, and by the appearance of a specialized class of hemocyte, the lamellocytes, which participate in the encapsulation and killing of the parasite. To study the molecular mechanisms of this response, we have overexpressed different genes in the hemocytes, by using the GAL4-upstream activating sequence system and a hemocytespecific Hemese-GAL4 driver. Multiple transgenes were tested, representing several important signaling pathways. We found that the proliferation response and the activation of lamellocyte formation are independent phenomena. A drastic increase in the number of circulating hemocytes is caused by receptor tyrosine kinases, such as Egfr, Pvr, and Alk, as well as by the downstream signaling components Ras85D and pointed, supporting the notion that the Ras-mitogen-activated protein kinase pathway regulates hemocyte numbers. In the case of Pvr and Alk, this phenotype also is accompanied by lamellocyte formation. By contrast, constitutively active hopscotch and hemipterous give massive activation of lamellocyte formation with little or no increase in total hemocyte numbers. This finding indicates that both the Jak͞Stat and the Jun kinase pathways affect lamellocyte formation. Still other signals, mediated by aop ACT , Toll 10b , and Rac1 expression, cause a simultaneous increase in lamellocyte and total cell numbers, and the same effect is seen when WNT signaling is suppressed. We conclude that the activation of a cellular response is complex and affected by multiple signaling pathways.

show abstract

“…While most species of naturally-occurring parasitic wasps of Drosophila are virulent and carry immune-suppressive factors, at least one avirulent strain Leptopilina boulardi, strain G486, has been identified. 3 Infection by this avirulent parasitic wasp leads first to the proliferation and differentiation of blood cell precursors in the hematopoietic organ, the lymph gland 4,5 ( Figure 1B), and then to encapsulation of the wasp egg. The three mature blood cells types are plasmatocytes, lamellocytes and crystal cells.…”

mentioning

confidence: 99%

Natural infection of D. melanogaster by virulent parasitic wasps induces apoptotic depletion of hematopoietic precursors

Chiu

Govind

2002

Cell Death Differ

View full text Add to dashboard Cite

Haemocyte changes in resistant and susceptible strains of D. melanogaster caused by virulent and avirulent strains of the parasitic wasp Leptopilina boulardi

Cited by 95 publications

References 27 publications

Genetic Analysis of Contributions of Dorsal Group and JAK-Stat92E Pathway Genes to Larval Hemocyte Concentration and the Egg Encapsulation Response in Drosophila

Genetic Analysis of Contributions of Dorsal Group and JAK-Stat92E Pathway Genes to Larval Hemocyte Concentration and the Egg Encapsulation Response in Drosophila

A directed screen for genes involved in Drosophila blood cell activation

Natural infection of D. melanogaster by virulent parasitic wasps induces apoptotic depletion of hematopoietic precursors

Contact Info

Product

Resources

About