A putative farnesoic acid O-methyltransferase (FAMeT) orthologue in Drosophila melanogaster (CG10527): Relationship to juvenile hormone biosynthesis?

• Published in: Peptides (New York, N.Y. : 1980) N.Y. : 1980), 2008-02, Vol.29 (2), p.242-251
• Main Authors: Burtenshaw, S.M., Su, P.P., Zhang, J.R., Tobe, S.S., Dayton, L., Bendena, W.G.
• Format: Article
• Language: English
• Subjects: Allatostatin; Amino Acid Sequence; Animals; Biological and medical sciences; Corpora Allata - chemistry; Corpora Allata - drug effects; Corpora Allata - metabolism; Drosophila melanogaster - enzymology; Drosophila melanogaster - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Fatty Acids, Monounsaturated - metabolism; Fatty Acids, Unsaturated - biosynthesis; Fatty Acids, Unsaturated - metabolism; Female; Fundamental and applied biological sciences. Psychology; Gene Deletion; Insect; Juvenile hormone regulation; Juvenile Hormones - biosynthesis; Larva - metabolism; Longevity - genetics; Male; Metamorphosis; Methyltransferases - genetics; Methyltransferases - metabolism; Molecular Sequence Data; Neuropeptides - pharmacology; Recombinant Proteins - biosynthesis; Recombinant Proteins - isolation & purification; Sequence Alignment; Sequence Homology, Amino Acid; Vertebrates: endocrinology
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2007.10.030

Juvenile hormones (JHs) are key regulators of both metamorphosis and adult reproductive processes. Farnesoic acid O-methyltransferase (FAMeT) is thought to be an important enzyme in the JH biosynthetic pathway, catalyzing methylation of farnesoic acid (FA) to methyl farnesoate (MF). Previous evidence in other insects suggested that FAMeT is rate limiting and regulated by a neuropeptide family, the allatostatins. A full-length cDNA encoding a 296 amino acid putative FAMeT has been isolated. A recombinant (r)FAMeT was cloned, expressed and a specific antiserum generated. rFAMeT was assayed for enzymatic activity using a radiochemical assay. In this assay, no activity was detected either with rFAMeT alone or when added to a corpus allatum CA extract. Immunohistochemical analysis was used to confirm the presence of FAMeT in the CA of Drosophila melanogaster ring gland. Analysis of MF, JHIII and JHB 3 release in wild type and mutant stocks in the presence and absence of Drome AST (PISCF-type) suggest that Drosophila FAMeT has little if any effect on sesquiterpenoid biosynthesis. Drome AST appears to have a select effect on JH bisepoxide biosynthesis and not MF or JHIII. Additional analysis of MF, JHIII and JHB 3 release in strains with a deficiency or decrease of FAMeT compared to wild type shows no significant decrease in MF, JHIII or JH bisepoxide synthesis. Deficiency strains that reduce the level of FAMeT showed reduced longevity relative to wildtype but this result may be due to other genetic influences.