Isolation and developmental expression of Xenopus FoxJ1 and FoxK1.

Abstract

xFoxJ1 and xFoxK1, two novel members of the fork head/winged helix family of transcription factors in Xenopus, have been identified by sequence homology to their mammalian orthologues. We here report the complete amino acid sequences of xFoxJ1, its pseudo-allelic version xFoxJ1', and of xFoxK1, the latter also comprising a fork-head-associated (FHA) domain. We have further analysed the temporal and spatial expression of both genes. xFoxJ1 transcripts were detected during gastrulation in the dorsal blastopore lip and in the animal half. A predominant feature of xFoxJ1 expression until the tailbud stage is its spotty pattern within the epidermis. xFoxK1 is maternally expressed and localized within the animal half during early cleavage stages. Zygotic transcription starts during neurulation and is initially restricted to neuroectoderm. As development proceeds, xFoxK1 is expressed in ectoderm- and mesoderm-derived tissues, like the branchial arches, brain, eye, otic vesicle, pronephros, somites and abdominal muscle precursors.