heterozygous embryo (B). Hox11 mRNA and Hoxa11eGFP are both expressed in the nephrogenic cap mesenchyme (white arrows in A’ and B’) and not in the cortical stroma cells. (TIF) Movie S1 Movie rendering of OPT analysis of a control kidney, immunostained with pan-cytokeratin (red) and cadherin 6 (green). The brown color represents unstained space filling of the rest of the dissected tissue. (MOV) Movie S2 Movie rendering of OPT analysis of two Hox10 triple mutant kidneys, immunostained with pan-cytokeratin (red) and cadherin 6 (green). The brown color represents unstained space filling of the rest of the dissected tissue. Of note, in mutant kidneys, some ureteric tips are not associated with nephrogenic mesen- chyme. (MOV) References 1. Dressler GR (2006) The cellular basis of kidney development. Annu Rev Cell Dev Biol 22: 509–529. 2. Kuure S, Vuolteenaho R, Vainio S (2000) Kidney morphogenesis: cellular and molecular regulation. Mech Dev 92: 31–45. 3. 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Mugford JW, Sipila P, Kobayashi A, Behringer RR, McMahon AP (2008) Hoxd11 specifies a program of metanephric kidney development within the intermediate mesoderm of the mouse embryo. Dev Biol 319: 396–405. PLoS ONE | www.plosone.org 10 August 2011 | Volume 6 | Issue 8 | e23410