Light-enhanced expression of Carbonic Anhydrase 4-like supports shell formation in the fluted giant clam Tridacna squamosa
| Autor: | Shit F. Chew, Yuen K. Ip, Clarissa Z. Y. Koh, Mei Lin Neo, Kum C. Hiong, Wai P. Wong, Celine Yen Ling Choo |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Open Reading Frames 03 medical and health sciences Carbonic Anhydrase IV 0302 clinical medicine Animal Shells Carbonic anhydrase Genetics Animals Tissue Distribution Cloning Molecular Mantle (mollusc) Phylogeny biology Giant clam Ctenidium Sequence Analysis DNA General Medicine Apical membrane biology.organism_classification Tridacna Bivalvia Up-Regulation Fluted giant clam Cell biology 030104 developmental biology 030220 oncology & carcinogenesis Zooxanthellae biology.protein |
| Zdroj: | Gene. 683:101-112 |
| ISSN: | 0378-1119 |
| DOI: | 10.1016/j.gene.2018.10.023 |
| Popis: | Giant clams represent symbiotic associations between a host clam and its extracellular zooxanthellae. They are able to grow in nutrient-deficient tropical marine environments and conduct light-enhanced shell formation (calcification) with the aid of photosynthates donated by the symbiotic zooxanthellae. In light, there is a high demand for inorganic carbon (Ci) to support photosynthesis in the symbionts and light-enhanced calcification in the host. In this study, we cloned and characterized a host Carbonic Anhydrase 4 homolog (CA4-like) from the whitish inner mantle of the giant clam Tridacna squamosa. The full cDNA coding sequence of CA4-like consisted of 1002 bp, encoding for 334 amino acids of 38.5 kDa. The host CA4-like was phenogramically distinct from algal CAs. The transcript level of CA4-like in the inner mantle was ~3-fold higher than those in the colorful outer mantle and the ctenidium. In the inner mantle, CA4-like was immunolocalized in the apical membrane of the seawater-facing epithelial cells, but absent from the shell-facing epithelium. Hence, CA4-like was positioned to catalyze the conversion of HCO3− to CO2 in the ambient seawater which would facilitate CO2 uptake. The absorbed CO2 could be converted back to HCO3− by the cytoplasmic CA2-like. As the protein abundance of CA4-like increased in the inner mantle after 6 or 12 h of light exposure, there could be an augmentation of the total CA4-like activity to increase Ci uptake in light. It is plausible that the absorbed Ci was allocated preferentially for shell formation due to the close proximity of the seawater-facing epithelium to the shell-facing epithelium in the inner mantle that contains only few zooxanthellae. |
| Databáze: | OpenAIRE |
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