Sequence and expression of zebrafish foxc1a and foxc1b, encoding conservedforkhead/winged helix transcription factors

Mouse Foxc1 (previously Mf1) is a member of the conserved forkhead/winged h elix transcription factor gene family. It is expressed in many mesodermal t issues including paraxial mesoderm of the trunk and head, prechondrogenic m esenchyme, branchial arches and developing kidney. Homozygous mutants die p erinatally with hydrocephalus and skeletal, cardiovascular, ocular and geni tourinary defects. Here, we report the cloning and expression of two zebraf ish foxc1 homologues, foxc1a and foxc1b. During gastrulation and somitogene sis both genes have similar expression patterns in the hypoblast, paraxial and presomitic mesoderm, somites and trunk adaxial cells. Expression in the somites is downregulated as they differentiate, but is maintained in the s clerotome. Later, some differences in expression pattern emerge. For exampl e, only foxc1a transcripts are detected in the pronephros primodia and in t he head mesoderm around the eyes, while only foxc1b is expressed in the pha ryngeal arches and pectoral fins. Early expression of foxc1a in the paraxia l mesoderm is modified in chordino, swir1, somitabun, and spadetail mutants . (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.