Expression pattern of MITF-A during kidney development.

<p><b>A-B)</b><i>In situ</i> hybridization of <i>Mitf-A</i> of E13.5 kidneys from wild-type (WT) and homozygous (HO) MITF-A transgenic embryos using an antisense RNA probe directed against a sequence encompassing exon 1A, specific for <i>Mitf-A</i>, and exon 1B common to <i>Mitf-A</i>, <i>Mitf-H</i>, <i>Mitf-C</i>, <i>Mitf-J</i> and <i>Mitf-Mc</i> isoforms. The inset shows the staining of E13.5 kidneys using the sense RNA probe. Magnifications are X100 (left panels), X200 (middle panels) and X400 (right panels). In WT kidneys <b>(A)</b> a weak staining is observed in branches of UB (black arrow), in S-shaped body (blue arrow) and in metanephric mesenchyme (asterisk). Consistent with the use of the Ksp-cadherin promoter, the signal in MITF transgenic kidneys <b>(B)</b> was strongly increased in UB and tips (black arrow), in ureteric tip (black arrow) and to a lesser extent in S-shaped body (blue arrow). <b>C)</b> <i>In situ</i> hybridization of <i>Mitf-A</i> in transgenic HO kidneys after laminin immunohistochemistry (red). Note <i>Mitf</i> expression in ureteric bud and tip (black arrow), in and S-shaped body (blue arrow). Magnification X400. Sections are representative images of 4 kidneys per genotype. <b>D</b>) Immunostaining of MITF-A in WT and HO MITF-A transgenic metanephroi at E13.5. Note the increase of MITF-A expression in UB stalks, tips and S-bodies. Magnification X400.