Sulf2 and 6OST are expressed in complementary regions of the developing Xenopus brain. Vibratome sections subsequent to in situ hybridisation (ISH) shows that the expression of Sulf2 is restricted to the ventral part of the midbrain and hindbrain, while the expression of 6OST is restricted dorsally. A and B are cross sections; C and D are sagittal sections through tailbud stage 28 embryos. Adapted from Winterbottom and Pownall, 2008.