Vol. 51 No. 8, 2012
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR):
An Apical Marker Protein of Ionocytes for Identifying
Hypo-osmoregulation in Gills of the Euryhaline Medaka Oryzias dancena
Chao-Kai
Kang1, Shu-Chuan Tsai2, Shang-Tao Lin1,
Wan-Yu Lo3,4, Tsung-Han Lee1,4,*, and Pung-Pung
Hwang5
1Department
of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
2Institute of Life Sciences, Central Taiwan University
of Science and Technology, Taichung 406, Taiwan
3Divisionof Surgery, Department of Medical Research, China Medical
University Hospital, Taichung 404, Taiwan
4Department of Biological Science and Technology, China Medical
University, Taichung 404, Taiwan
5Institute of Cellular and Organismic Biology, Academia Sinica,
Nankang, Taipei 115, Taiwan
Chao-Kai Kang, Shu-Chuan Tsai, Shang-Tao
Lin, Wan-Yu Lo, Tsung-Han Lee, and Pung-Pung Hwang (2012) This
study used a monoclonal antibody against the human cystic fibrosis
transmembrane conductance regulator (CFTR) to characterize its
expression in gills of the brackish medaka Oryzias dancena. Whole-mount double
immunofluorescence staining of gills revealed that the CFTR protein was
localized in apical membranes of Na+, K+-ATPase-immunoreactive ionocytes in gills
of seawater (SW)-acclimated medaka. Immunoreactive signals of the
CFTR protein were detected by the antibody in gills of SW medaka rather
than in those of freshwater (FW) fish. Furthermore, the
full-length complementary (c)DNA of Odcftr
was cloned and identified from gill tissues to evaluate specific
affinities of the CFTR antibody. Using the RT-PCR to survey gene
expressions in various tissues, Odcftr
was prominently expressed in gills of the brackish medaka. Higher
messenger (m)RNA levels of Odcftr were found in gills of medaka
acclimated to environments with increasing salinities. The
present study validated the salinity-dependent expression of the CFTR
in branchial ionocytes of the brackish medaka and illustrated that the
CFTR protein is a marker of the hypo-osmoregulatory role of the gill
epithelium of this euryhaline teleost.
Key words: CFTR, Medaka, Ionocytes, Gills,
Hypo-osmoregulation.
*Correspondence: Tel: 886-4-22856141. Fax:
886-4-22874740. E-mail:thlee@email.nchu.edu.tw
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