Fig. 1. Conservation of upstream sequences between vertebrate Pax2 genes. (A) The promoter and proximal (P), intermediate (I) and distal (D) homology regions of the human, mouse and Fugu rubripes Pax2 genes are shown with their degree of sequence identity and nucleotide positions relative to the transcription start sites. The Fugu gene was identified as Pax2.1 by comparison of its exon 1 with those of the two zebrafish Pax2 genes (Pfeffer et al., 1998). (B,C) Conservation of the box D (B) and promoter of Pax2 (C). Only those nucleotides of the Fugu (f) Pax2.1 gene that differ from the mouse (m) sequence are shown. A high-affinity Pax-binding site in box D is aligned with the Pax2/5/8 consensus sequence (Czerny and Busslinger, 1995) and with element E1 of the MHB-specific enhancer of Pax5 (Pfeffer et al., 2000). An arrowhead points to the insertion of 26 nucleotides in the Fugu promoter, and a red arrow indicates the region of heterogeneous transcription initiation of mouse Pax2 (Ryan et al., 1995).