Correlating global gene regulation to morphogenesis and maturation in the chick extra-embryonic vascular system

Formation of blood vessels requires the concerted regulation of an unknown number of genes in a spatial-, time- and dosage-dependent manner. We investigated vascular development in vivo by determining global gene regulation throughout the formation of the chick chorio-allantoic membrane (CAM). Our study provides a comprehensive molecular map of vascular maturation during developmental angiogenesis and might thus be a valuable resource to streamline further research of candidates susceptible to mediate pathological angiogenesis. The developmental stage of the embryos was determined after isolation of the CAM according to Hamburger & Hamilton (HH) (1992). CAMs were isolated from embryos at developmental day E5 (HH26), E7 (HH30), E10 (HH>35) and E14 (HH40), (n=3 embryos/day). mRNA was isolated and hybridized to Affymetrix chicken GeneChips using the Affymetrix standard protocol. We compared one embryo at a lower HH stage to three embryos at a more advanced HH stage and repeated the comparison with two more embryos. Overall, we compared expression between E7 and E5, E10 and E5, E14 and E5, E10 and E7 and E14 and E10.