The murine Wilms tumor suppressor gene (wt1) locus

The Wilms tumor suppressor gene WT1 plays a crucial role in the etiology of various human diseases as well as in the development of specific organs including the kidneys, gonads and the spleen. At present the human as well as the Fugu wt1 locus have been characterized. We have used a PAC clone to analyze the murine wt1 locus and report here the structure of the wt1 gene as well as a characterization of the nine wt1 introns regarding their size and sequence at the exon/intron and intron/exon boundaries. In addition we provide a restriction map of the murine wt1 locus which should prove useful for the cloning of various constructs designed for the generation of mouse models. Prompted by the existence of a WT1 antisense transcript in humans we also examined strand-specific transcription at the murine wt1 locus. Our analysis suggests that there is no detectable antisense transcription of sequences within or immediately downstream of wt1 exon 1. We find, however, evidence for a divergent transcript which encompasses sequences at and around minor transcriptional initiation sites of wt1 and which is transcribed in the opposite direction. Despite the very high degree of similarity between the human and the murine wt1 sequence and expression as well as the presence of divergent transcripts in both cases, the existence of antisense transcription does not seem to be conserved between the two species.