Fig. 9

Luciferase assay analysis of Lhx3 and Hex regulatory sequences. a, d Region 5′ of Lhx3 gene (a) or Hex gene (d) shows three putative Pitx binding sites (BS1, BS2, BS3). Numbers show the distance before the start codon. Two luciferase reporter gene constructs are tested in amphioxus embryos with 0 or 3 Pitx binding sites mutated in Lhx3 (a) or Hex (d) promoter. b, e Histogram shows relative levels of luciferase expression for a construct including 0 Pitx binding sites mutated, a group co-injection of Pitxc mRNA with the construct, a control luciferase vector pGL3 without Lhx3 or Hex sequence. c, f Histogram shows relative levels of luciferase expression for each construct (0 or 3 Pitx binding sites mutated), a control luciferase vector pGL3. Significance determined by t-test is indicated by asterisks: *P < 0.05, **P < 0.01, ***P < 0.001