Table 1. Expression of CXCL12, CXCR7 and CXCR7 mRNA during nephrogenesis.

	CXCL12	CXCR7	CXCR4
ureteric bud tip (ep)	−	early: +	early: +
		late: (−)	late: (−)
cap mesenchyme (mes)	(+)	(+)	early: (−)
			late: +
pretubular aggregate (mes→ep)	(+)	+	+
renal vesicle (ep)	+	+	−
comma-shaped body (ep)	+	+	−
S-shaped body (ep)	+	+	−
capillary-loop glomerulus (ep)	+	+	−
mature glomerulus	+	+	+
podocytes (ep)	+	+	−
endothelial cells	−	−	+
mesangium cells	(+)	−	−

Mapping of CXCL12, CXCR7, and CXCR4 expression was performed using the markers WT1 (dual in situ hybridization) and Podocin as well as VEGFR-2 (dual immunofluorescence). +, strong expression; (+) weak expression; (−) very weak expression; − no expression. ep, epithelial cells; mes, mesenchymal cells; mes→ep, mesenchymal-to-epithelial transition.