Transcription patterns of four different fork head/HNF-3 related genes (XFD-4, 6, 9 and 10) in Xenopus laevis embryos.

We have isolated and sequenced four different members of the Xenopus fork head domain related multigene family (XFD-4, 6, 9 and 10). These genes show a high degree of sequence conservation inside the evolutionary conserved fork head domain but they completely diverge outside this region. All four XFD genes are transcribed during embryogenesis but they are activated at different developmental stages. To investigate the localisation of transcripts we performed whole mount in situ hybridizations. We detected XFD-4 transcripts in somitogenic mesoderm, pronephros, pronephric duct, heart and the tip of the tail. XFD-6 transcripts were confined to migrating neural crest cells originating from the mesencephalon and rhombencephalon. Transcriptional activity of XFD-9 was observed in the region of rotating somites and the posterior part of the pronephric duct. XFD-10 transcripts were detected in lateral cell stripes located at the hyoid and the anterior branchial arches.