Homeoboxes in sea anemones (Cnidaria:Anthozoa): a PCR-based survey of Nematostella vectensis and Metridium senile.
Homeobox genes belong to a phylogenetically widespread family of regulatory genes that play important roles in pattern formation and cell-fate specification in several model systems (e.g., Drosophila, mouse, and C. elegans). Although the evolution of many classes of homeobox genes predates the diversification of the Bilateria, comparatively little is known about homeobox genes in outgroups to the Bilateria, such as the Cnidaria. We used the polymerase chain reaction to recover 12 partial homeoboxes from 2 species of sea anemones, Metridium senile and Nematostella vectensis (phylum Cnidaria; class Anthozoa). These homeoboxes appear to represent 9 distinct, mutually paralogous homeobox genes, 5 of which belong to previously identified cnidarian homeobox classes, and 4 of which appear to represent previously unidentified classes. The evolutionary relationships between the homeodomains of sea anemones and of bilaterian animals were assessed through database searches and phylogenetic analyses. As many as 5 of the anemone homeoboxes may belong to the Hox class, which suggests that the Hox gene complement of cnidarians is larger than previously expected. Homologs of the even-skipped gene of Drosophila were also identified in both Metridium and Nematostella.
Finnerty
J R
JR
Department of Organismal Biology and Anatomy, University of Chicago, Illinois 60637, USA.
Martindale
M Q
MQ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D002107:Caenorhabditis / Q000235:genetics; D003001:Cloning, Molecular; D004330:Drosophila / Q000235:genetics; D019143:Evolution, Molecular; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D007256:Information Systems; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012615:Sea Anemones / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D018398:Homeodomain Proteins; D011994:Recombinant Proteins