title: Over one-half billion years of head conservation? Expression of an ems class gene in Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa).
abstract: We report the isolation of an empty spiracles class homeodomain-containing gene, Cn-ems, from the hydrozoan Hydractinia symbiolongicarpus, the first gene of this class characterized in a lower metazoan. Cn-ems was found to be expressed in the head of gastrozooids, specifically in endodermal epithelial cells of the taeniolae of the hypostome. Cn-ems is not expressed in gonozooids, which lack taeniolae. Experimental conversion of the posterior region of the planula larva into head structures up-regulates expression of the gene. These findings establish that the association of ems-class genes with head structures preceded the evolution of bilateral symmetry.
authors.affiliation: The Institute for Nature Conservation Research, Tel Aviv University, Tel Aviv 69978, Israel. mokady@post.tau.ac.il
authors.forename: O
authors.initials: O
authors.lastname: Mokady
authors.forename: M H
authors.initials: MH
authors.lastname: Dick
authors.forename: D
authors.initials: D
authors.lastname: Lackschewitz
authors.forename: B
authors.initials: B
authors.lastname: Schierwater
authors.forename: L W
authors.initials: LW
authors.lastname: Buss
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017124:Conserved Sequence; D029721:Drosophila Proteins; D019143:Evolution, Molecular; D016678:Genome; D006257:Head / Q000196:embryology; D018398:Homeodomain Proteins / Q000235:genetics*; D006829:Hydra / Q000196:embryology / Q000235:genetics*; D008969:Molecular Sequence Data; D000099260:Empty Spiracles Homeobox Proteins
chemical_list: D029721:Drosophila Proteins; D018398:Homeodomain Proteins; C093054:ems protein, Drosophila; D000099260:Empty Spiracles Homeobox Proteins