Induction of cxcr1 at 36 hpf does not enhance HSPC emergence. Scl-β:GFP;kdrl:mCherry transgenic animals were injected with DNA encoding cxcr1 or empty vector (Control) and gene expression was induced by heat shock at 36 hpf. Uninjected animals were treated with DMSO or PGE₂ beginning at the 16-somite stage and served as additional negative and positive controls. The AGM region was imaged from 38–49 hpf. (a–e) Representative fluorescence images showing sclβ-GFP (a), kdrl:mCherry (b), merged GFP and mCherry channels (c), sclβ⁺ spots identified by digital image analysis and an overlay image with somite boundaries and dorsal aorta (DA) and posterior cardinal vein (PCV) marked (e). Bar = 70 µm. (f) Time series plot showing the cumulative numbers of sclβ:GFP⁺ cells in the AGM of each group (n = 9 for PGE2, n = 5 for DMSO, n = 10 for control, and n = 6 for CXCR1). Colored bands represent 95% confidence intervals. The experiment was repeated twice with similar results; a representative experiment is shown.