Cloning, characterization, and developmental expression of a putative farnesoic acid O-methyl transferase in the female edible crab Cancer pagurus

摘要

Farnesoic acid methyl transferase (FAMTase) catalyzes methylation of farnesoic acid to yield the crustacean juvenoid, methyl farnesoate (MF). A full-length cDNA encoding a 275 amino acid putative FAMTase has been isolated from the mandibular organ of the female edible crab (Cancer pagurus) by reverse transcriptase-polymerase chain reaction in conjunction with cDNA library screening. A high degree of sequence identity was found between this and other putative crustacean FAMTases. Conceptual translation and protein sequence analysis suggested that phosphorylation could occur at multiple sites in the FAMTase. This finding is consistent with the recent observation that endogenous FAMTase activity in mandibular organ extracts can be regulated by phosphorylation in vitro. We demonstrated that the recombinant FAMTase could be expressed as a LacZ-fusion protein in Escherichia coli and have undertaken its partial purification from inclusion bodies. In an established assay system, the recombinant FAMTase lacked activity.