New insights into Drosophila larval haemocyte functions through genome-wide analysis.
Drosophila blood cells or haemocytes comprise three cell lineages, plasmatocytes, crystal cells and lamellocytes, involved in immune functions such as phagocytosis, melanisation and encapsulation. Transcriptional profiling of activities of distinct haemocyte populations and from naive or infected larvae, was performed to find genes contributing to haemocyte functions. Of the 13 000 genes represented on the microarray, over 2500 exhibited significantly enriched transcription in haemocytes. Among these were genes encoding integrins, peptidoglycan recognition proteins (PGRPs), scavenger receptors, lectins, cell adhesion molecules and serine proteases. One relevant outcome of this analysis was the gain of new insights into the lamellocyte encapsulation process. We showed that lamellocytes require betaPS integrin for encapsulation and that they transcribe one prophenoloxidase gene enabling them to produce the enzyme necessary for melanisation of the capsule. A second compelling observation was that following infection, the gene encoding the cytokine Spatzle was uniquely upregulated in haemocytes and not the fat body. This shows that Drosophila haemocytes produce a signal molecule ready to be activated through cleavage after pathogen recognition, informing distant tissues of infection.
Irving
Phil
P
UPR 9022 du CNRS, IBMC, 15 rue René Descartes, 67084 Strasbourg, France.
Ubeda
Jean-Michel
JM
Doucet
Daniel
D
Troxler
Laurent
L
Lagueux
Marie
M
Zachary
Daniel
D
Hoffmann
Jules A
JA
Hetru
Charles
C
Meister
Marie
M
D000818:Animals; D004156:Catechol Oxidase / Q000235:genetics / Q000378:metabolism; D019070:Cell Lineage; D004330:Drosophila / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004792:Enzyme Precursors / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000472:pathogenicity; D005216:Fat Body / Q000378:metabolism / Q000382:microbiology; D020869:Gene Expression Profiling; D016678:Genome; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D039001:Integrin alpha Chains; D016023:Integrins / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D016982:Micrococcus luteus / Q000472:pathogenicity
D029721:Drosophila Proteins; D004792:Enzyme Precursors; D039001:Integrin alpha Chains; D016023:Integrins; C082188:if protein, Drosophila; C086179:spz protein, Drosophila; C038451:pro-phenoloxidase; D004156:Catechol Oxidase