Close Association of Carbonic Anhydrase (CA2a and CA15a), Na(+)/H(+) Exchanger (Nhe3b), and Ammonia Transporter Rhcg1 in Zebrafish Ionocytes Responsible for Na(+) Uptake.

ABSTRACT: Freshwater (FW) fishes actively absorb salt from their environment to tolerate low salinities. We previously reported that vacuolar-type H(+)-ATPase/mitochondrion-rich cells (H-MRCs) on the skin epithelium of zebrafish larvae (Danio rerio) are primary sites for Na(+) uptake. In this study, in an attempt to clarify the mechanism for the Na(+) uptake, we performed a systematic analysis of gene expression patterns of zebrafish carbonic anhydrase (CA) isoforms and found that, of 12 CA isoforms, CA2a and CA15a are highly expressed in H-MRCs at larval stages. The ca2a and ca15a mRNA expression were salinity-dependent; they were upregulated in 0.03 mM Na(+) water whereas ca15a but not ca2a was down-regulated in 70 mM Na(+) water. Immunohistochemistry demonstrated cytoplasmic distribution of CA2a

SUBMITTER: Ito Y 

PROVIDER: S-EPMC3615223 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature