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Are N iemann‐ P ick type C proteins key players in cnidarian–dinoflagellate endosymbioses?
Author(s) -
Dani Vincent,
Ganot Philippe,
Priouzeau Fabrice,
Furla Paola,
Sabourault Cecile
Publication year - 2014
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12876
Subject(s) - biology , symbiodinium , dinoflagellate , symbiosis , sea anemone , zooxanthellae , gene , anthozoa , coral , botany , genetics , ecology , bacteria
Abstract The symbiotic interaction between cnidarians, such as corals and sea anemones, and the unicellular algae S ymbiodinium is regulated by yet poorly understood cellular mechanisms, despite the ecological importance of coral reefs. These mechanisms, including host–symbiont recognition and metabolic exchange, control symbiosis stability under normal conditions, but also lead to symbiosis breakdown (bleaching) during stress. This study describes the repertoire of the sterol‐trafficking proteins N iemann‐ P ick type C ( NPC 1 and NPC 2) in the symbiotic sea anemone A nemonia viridis . We found one NPC 1 gene in contrast to the two genes ( NPC 1 and NPC 1L1) present in vertebrate genomes. While only one NPC 2 gene is present in many metazoans, this gene has been duplicated in cnidarians, and we detected four NPC 2 genes in A . viridis . However, only one gene ( A v NPC 2‐d) was upregulated in symbiotic relative to aposymbiotic sea anemones and displayed higher expression in the gastrodermis (symbiont‐containing tissue) than in the epidermis. We performed immunolabelling experiments on tentacle cross sections and demonstrated that the A v NPC 2‐d protein was closely associated with symbiosomes. In addition, A v NPC 1 and A v NPC 2‐d gene expression was strongly downregulated during stress. These data suggest that Av NPC 2‐d is involved in both the stability and dysfunction of cnidarian–dinoflagellate symbioses.