Effect of inducers and inhibitors on the expression of bcs genes involved in cypris larval attachment and metamorphosis of the barnacles Balanus amphitrite.

We examined the expression of six barnacle cypris larva-specific gene (bcs) cDNAs (bcs-1, -2, -3, -4,- 5, and -6), the bcs genes, by using Northern blot analysis under various conditions that induced or inhibited cypris larval attachment and metamorphosis. Inducers of larval attachment and metamorphosis, such as a neurotransmitter, tended to increase the expression of bcs mRNAs. All inhibitors of larval attachment and metamorphosis, such as G protein-coupled receptor agonists/antagonists, inhibitors of tyrosine kinase-linked receptors and inhibitors of their signal transduction, suppressed the expression of bcs-6 mRNA alone, but affected differentially other bcs genes. These results strongly suggest that the bcs-6 product plays a key role in triggering the attachment and metamorphosis of cypris larvae into juvenile barnacles. The roles of four late bcs genes (bcs-3,-4, -5 and -6) are discussed.