The Drosophila VEGF receptor homolog is expressed in hemocytes.
Several signalling pathways have been defined by studies of genes originally characterised in Drosophila. However, some mammalian signalling systems have so far escaped discovery in the fly. Here, we describe the identification and characterisation of fly homologs for the mammalian vascular endothelial growth factor/platelet derived growth factor (VEGF/PDGF) and the VEGF receptor. The Drosophila factor (DmVEGF-1) gene has two splice variants and is expressed during all stages, the signal distribution during embryogenesis being ubiquitous. The receptor (DmVEGFR) gene has several splice variants; the variations affecting only the extracellular domain. The most prominent form is expressed in cells of the embryonic haematopoietic cell lineage, starting in the mesodermal area of the head around stage 10 of embryogenesis. Expression persists in hemocytes as embryonic development proceeds and the cells migrate posteriorly. In a fly strain carrying a deletion uncovering the DmVEGFR gene, hemocytes are still present, but their migration is hampered and the hemocytes remain mainly in the anterior end close to their origin. These data suggest that the VEGF/PDGF signalling system may regulate the migration of the Drosophila embryonic haemocyte precursor cells.
Heino
T I
TI
Institute of Biotechnology, Viikki Biocenter, PB 56 (Viikinkaari 9), FIN-00014, University of Helsinki, Helsinki, Finland.
Kärpänen
T
T
Wahlström
G
G
Pulkkinen
M
M
Eriksson
U
U
Alitalo
K
K
Roos
C
C
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics*; D016228:Endothelial Growth Factors / Q000145:classification / Q000235:genetics*; D015870:Gene Expression; D017344:Genes, Insect; D006434:Hemocytes / Q000166:cytology*; D006801:Humans; D008222:Lymphokines / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D020794:Receptor Protein-Tyrosine Kinases / Q000145:classification / Q000235:genetics*; D017978:Receptors, Growth Factor / Q000145:classification / Q000235:genetics*; D040262:Receptors, Vascular Endothelial Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; D017978:Receptors, Growth Factor; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020794:Receptor Protein-Tyrosine Kinases; D040262:Receptors, Vascular Endothelial Growth Factor