Molecular characterization, cellular localization, and light-enhanced expression of Beta-Na+/H+ Exchanger-like in the whitish inner mantle of the giant clam, Tridacna squamosa, denote its role in light-enhanced shell formation
| Autor: | Caryn Z. Pang, Wai P. Wong, Anh H. Cao-Pham, Mel V. Boo, Kum C. Hiong, Shit F. Chew, Yuen K. Ip, Mei Lin Neo, Celine Y. L. Choo |
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| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
chemistry.chemical_classification biology General Medicine Apical membrane biology.organism_classification Epithelium Amino acid Fluted giant clam 03 medical and health sciences Sodium–hydrogen antiporter 030104 developmental biology 0302 clinical medicine medicine.anatomical_structure chemistry 030220 oncology & carcinogenesis Darkness Genetics medicine Biophysics Mantle (mollusc) Cellular localization |
| Zdroj: | Gene. 695:101-112 |
| ISSN: | 0378-1119 |
| Popis: | The fluted giant clam, Tridacna squamosa, lives in symbiosis with photosynthetic zooxanthellae, and can engage in light-enhanced growth and shell formation. Light-enhanced shell formation necessitates the elimination of excess H+ from the extrapallial fluid adjacent to the shell. This study aimed to clone Na+/H+ Exchanger (NHE) from the whitish inner mantle adjacent to the extrapallial fluid of T. squamosa, to determine its cellular and subcellular localization, and to evaluate the effect of light exposure on its mRNA expression level and protein abundance therein. The complete coding cDNA sequence of NHE obtained was identified as a homolog of beta NHE (βNHE-like). It consisted of 2925 bp, encoding for a polypeptide of 974 amino acids and 107.1 kDa, and was expressed predominantly in the inner mantle. There, βNHE-like was localized in the apical membrane of the seawater-facing epithelium by immunofluorescence microscopy. After exposure to light for 12 h, the seawater-facing epithelium of the inner mantle displayed consistently stronger immunostaining than that of the control exposed to 12 h of darkness. Western blotting confirmed that light exposure significantly enhanced the protein abundance of βNHE-like in the inner mantle. These results denote that some of the excess H+ generated during light-enhanced shell formation can be excreted through the light-dependent βNHE-like of the seawater-facing epithelium to minimize the impact on the whole-body pH. Importantly, the excreted H+ could dehydrate exogenous HCO3−, and facilitate the absorption of inorganic carbon through the seawater-facing epithelium dedicated for light-enhanced shell formation due to its close proximity with the shell-facing epithelium. Nucleotide symbol combinations Pairs: R = A/G; W = A/T; Y = C/T. Triples: D = A/G/T. |
| Databáze: | OpenAIRE |
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