PMID:22174750

Citation	Riviere, G, Fellous, A, Franco, A, Bernay, B and Favrel, P (2011) A crucial role in fertility for the oyster angiotensin-converting enzyme orthologue CgACE. PLoS ONE 6:e27833
Abstract	Angiotensin-converting enzyme (ACE) is a highly conserved metallopeptidase. In mammals, the somatic isoform governs blood pressure whereas the germinal isoform (tACE) is required for fertility. In Ecdysozoans, ACE-like enzymes are implicated in reproduction. Despite ACE orthologues being present from bacteria to humans, their function(s) remain(s) unknown in distant organisms such as Lophotrochozoans. In silico analysis of an oyster (Crassostrea gigas) EST library suggested the presence of an ACE orthologue in molluscs. Primer walking and 5'-RACE revealed that the 1.9 kb cDNA encodes CgACE, a 632 amino acid protein displaying a conserved single active site and a putative C-terminal transmembrane anchor, thus resembling human tACE, as supported by molecular modelling. FRET activity assays and Maldi-TOF spectrometry indicated that CgACE is a functional dipeptidyl-carboxypeptidase which is active on Angiotensin I and sensitive to ACE inhibitors and chloride ion concentration. Immunocytochemistry revealed that, as its human counterpart, recombinant CgACE is synthesised as a transmembrane enzyme. RT-qPCR, in-situ hybridization and immunohistochemistry shed light on a tissue, and development stage, specific expression pattern for CgACE, which is increased in the gonad during spermatogenesis. The use of ACE inhibitors in vivo indicates that the dipeptidase activity of CgACE is crucial for the oyster fertilization. Our study demonstrates that a transmembrane active ACE is present in the oyster Crassostrea gigas, and for the first time ascribes a functional role for ACE in Lophotrochozoans. Its biological function in reproduction is conserved from molluscs to humans, a finding of particular evolutionary interest especially since oysters represent the most important aquaculture resource worldwide.
Links	PubMed PMC3235092 Online version:10.1371/journal.pone.0027833
Keywords	Amino Acid Sequence; Angiotensin-Converting Enzyme Inhibitors/pharmacology; Animals; Fertility/drug effects; Gene Expression Regulation, Enzymologic/drug effects; Gonads/cytology; Gonads/drug effects; Gonads/enzymology; Humans; Models, Molecular; Molecular Sequence Data; Ostreidae/cytology; Ostreidae/drug effects; Ostreidae/enzymology; Peptidyl-Dipeptidase A/chemistry; Peptidyl-Dipeptidase A/genetics; Peptidyl-Dipeptidase A/metabolism; Phylogeny; RNA, Messenger/genetics; RNA, Messenger/metabolism; Sequence Homology, Amino Acid; Structural Homology, Protein
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CRAGI:G9HQL1		GO:0080154: regulation of fertilization	ECO:0000269:		P		Fig4A: RT-qPCR reveals CgACE mRNA increases in germinal area of male gonads: spermatogonia, spermatocytes I & II. Fig6:all inhibitors induced dose-dependant decrease in fecundation rate: p less than 0.0001. This indicated CgACE crucial for fertility in C.gigas.	complete CACAO 4475

References

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