LIFE STAGE AND TISSUE-SPECIFIC EXPRESSION OF THE HOMEOBOX GENE CNOX1-PC OF THE HYDROZOAN PODOCORYNE CARNEA

We have isolated from the hydrozoan Podocoryne carnea a genomic clone and the corresponding cDNA of a homeobox gene. This gene, called cnox1 -Pc, is most closely related to the lab class of homeobox genes. In th e life cycle of P. carnea, which involves an asexually reproducing, se dentary polyp and a sexual planktonic medusa stage, we found cnox1-Pc transcripts specifically expressed in the medusa stage. Expression stu dies on isolated medusa organs and tissues indicate that the message i s absent in the tentacles and the feeding and sexual organ of the medu sa and present in the striated muscle cells. During medusa bud develop ment, expression of cnox1-Pc can be correlated with the development of the striated muscle tissue, a cell type only found in the medusa. The results suggest that cnox1-pc is involved in pattern formation of the medusa of P. carnea and might have a regulatory role in the different iation of striated muscle. (C) 1995 Academic Press,Inc.