A MOX HOMEOBOX GENE IN THE GASTROPOD MOLLUSK HALIOTIS-RUFESCENS IS DIFFERENTIALLY EXPRESSED DURING LARVAL MORPHOGENESIS AND METAMORPHOSIS

We have isolated a homeobox-containing cDNA from the gastropod mollusc Haliotis rufescens that is most similar to members of the Mox homeobo x gene class, The derived Haliotis homeodomain sequence is 85% identic al to mouse and frog Mox-2 homeodomains and 88.9% identical to the par tial cnidarian cnox5-Hm homeodomain. Quantitative reverse transcriptio n-polymerase chain reaction analysis of mRNA accumulation reveals that this gene, called HruMox, is expressed in the larva, but not in the e arly embryo, Transcripts are most prevalent during larval morphogenesi s from trochophore to veliger. There are also transient increases in t ranscript prevalence 1 and 3 days after the intitiation of metamorphos is from veliger to juvenile. The identification of a molluscan Mox hom eobox gene that is more closely related to vertebrate genes than other protostome (e.g. Drosophila) genes suggests the Mox class of homeobox genes may consist of several different families that have been conser ved through evolution, (C) 1997 Federation of European Biochemical Soc ieties.