Identification of two carbonic anhydrases in the mantle of the European Abalone Haliotis tuberculata (Gastropoda, Haliotidae): phylogenetic implications.
Carbonic anhydrases (CAs) represent a diversified family of metalloenzymes that reversibly catalyze the hydration of carbon dioxide. They are involved in a wide range of functions, among which is the formation of CaCO(3) skeletons in metazoans. In the shell-forming mantle tissues of mollusks, the location of the CA catalytic activity is elusive and gives birth to contradicting views. In the present paper, using the European abalone Haliotis tuberculata, a key model gastropod in biomineralization studies, we identified and characterized two CAs (htCA1 and htCA2) that are specific of the shell-forming mantle tissue. We analyzed them in a phylogenetic context. Combining various approaches, including proteomics, activity tests, and in silico analyses, we showed that htCA1 is secreted but is not incorporated in the organic matrix of the abalone shell and that htCA2 is transmembrane. Together with previous studies dealing with molluskan CAs, our findings suggest two possible modes of action for shell mineralization: the first mode applies to, for example, the bivalves Unio pictorum and Pinctada fucata, and involves a true CA activity in their shell matrix; the second mode corresponds to, for example, the European abalone, and does not include CA activity in the shell matrix. Our work provides new insight on the diversity of the extracellular macromolecular tools used for shell biomineralization study in mollusks.
UMR CNRS 6282 Biogéosciences, Université de Bourgogne, Dijon, France. nathalie.le-roy@u-bourgogne.fr
Nathalie
N
LE Roy
Benjamin
B
Marie
Béatrice
B
Gaume
Nathalie
N
Guichard
Sidney
S
Delgado
Isabelle
I
Zanella-Cléon
Michel
M
Becchi
Stéphanie
S
Auzoux-Bordenave
Jean-Yves
JY
Sire
Frédéric
F
Marin
D060105:Animal Shells / Q000201:enzymology*; D000818:Animals; D001483:Base Sequence; D002113:Calcification, Physiologic / Q000235:genetics / Q000502:physiology*; D002256:Carbonic Anhydrases / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D049851:Gastropoda / Q000201:enzymology* / Q000235:genetics; D016013:Likelihood Functions; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D040901:Proteomics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D017931:DNA Primers; D018076:DNA, Complementary; D002256:Carbonic Anhydrases