Fig. S5

Dynamic alterations in renal transcription factors in lib mutants show some trends analogous to wild-type embryo caudal domains, but with some differences. Gene expression patterns of transcription factors in nephron progenitors in wild-type embryos compared with lib mutant embryos at the 20, 22, 24, and 28 somite stage. Embryos are shown in lateral views with anterior to the left, and have been stained by whole-mount in situ hybridization to mark kidney expression (purple) and the somites with mhc (red). Black lines indicate areas of high gene expression, and numbers correspond to the adjacent somite position. The spatial distributions of pou3f3a and pou3f3b transcripts in lib mutants were continually expressed in rostral regions between 20 and 28 somites (28 somite stage not shown). The distribution of mecom changed progressively in both wild-types and lib throughout the 20–28 somite stages. The distribution of emx1 and gata3 transcripts was unaltered in wild-types between the 20 and 28 somite stages, whereas lib had progressive restrictions of these transcripts to caudal populations.