Characterisation of the genomic structure of chick Fgf8.

The Fgf8 gene encodes a series of secreted signalling molecules important in the normal development of the face, brain and limbs. The genomic structure of the chick Fgf8 gene has been analysed and compared to the human and mouse sequences. Divergence between the chick, human and mouse genomic structure was observed. Data indicates that the long alternatively spliced form of exon 1b observed in mouse and exon 1c observed in human and mouse do not exist in the chick Fgf8 gene. RT-PCR analysis indicates that chick Fgf8, like its mouse and human counterpart is alternatively spliced. This data along with the genomic structure data indicates that in the chick there are only two isoforms of Fgf8. This is in contrast to the human and mouse, where evidence suggests that there are 4 and 8 isoforms, respectively. Approximately 400 bp of intron 1d is highly conserved between chick, human and mouse genomic sequences. Using TRANSFAC possible conserved regulatory element binding sites within this domain were identified.