Characterisation of an amphioxus Fringe gene and the evolution of the vertebrate segmentation clock.
In mouse and chick embryos, cyclic expression of lunatic fringe has an important role in the regulation of mesoderm segmentation. We have isolated a Fringe gene from the protochordate amphioxus. Amphioxus is the closest living relative of the vertebrates, and has mesoderm that is definitively segmented in a manner that is similar to, and probably homologous with, that of vertebrates. AmphiFringe is placed basal to vertebrate Fringe genes in molecular phylogenetic analyses, indicating that the duplications that formed radical-, manic- and lunatic fringe are specific to the vertebrate lineage. AmphiFringe expression was detected in the anterior neural plate of early neurulae, where it resolved into a series of segmental patches by the mid-neurulae stage. No AmphiFringe transcripts were detected in the mesoderm. Based on these observations, we propose a model depicting a successive recruitment of Fringe in the maintenance then regulation of segmentation during vertebrate evolution.
Mazet
Françoise
F
School of Animal and Microbial Sciences, The University of Reading, Whiteknights, PO Box 228, Reading RG6 6AJ, UK. f.mazet@reading.ac.uk
Shimeld
Sebastian M
SM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019521:Body Patterning / Q000235:genetics*; D002816:Chordata, Nonvertebrate / Q000235:genetics*; D017931:DNA Primers; D029721:Drosophila Proteins; D019143:Evolution, Molecular; D015870:Gene Expression; D017403:In Situ Hybridization; D016013:Likelihood Functions; D008648:Mesoderm / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics*; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D029721:Drosophila Proteins; D017351:N-Acetylglucosaminyltransferases; C090576:fng protein, Drosophila