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Over one-half billion years of head conservation? Expression of an ems class gene in Hydractinia symbiolongicarpus (Cnidaria: Hydrozoa)

1998; National Academy of Sciences; Volume: 95; Issue: 7 Linguagem: Inglês

10.1073/pnas.95.7.3673

1091-6490

Ofer Mokady, Matthew H. Dick, Dagmar Lackschewitz, Bernd Schierwater, Leo W. Buss,

Developmental Biology and Gene Regulation

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.