Electroneutral cation-Cl− cotransporters NKCC2β and NCCβ expressed in the intestinal tract of Japanese eel Anguilla japonica

Aquaporin expression in the Japanese medaka (Oryzias latipes, Temminck & Schlegel) in FW and SW: challenging the paradigm for intestinal water transport?

“…Furthermore, the transcript increased in the kidney in FW and in the intestine in SW in line with its recognized role in hypotonic urine production in FW and intestinal salt absorption in SW, respectively. The absorptive isoform, NKCC2, has been found in the intestine and kidney of many teleosts [winter flounder, Pseudopleuronectes americanus (O'Grady et al, 1986); olive flounder, Paralichythys olivaceus (Kim et al, 2013); rainbow trout, O. mykiss (Aguenaou et al, 1989); eel Watanabe et al, 2011)]. In addition to its main function as carrier of Na + , K + and Cl -transport, the NKCC1 isoform may also transport significant amounts of water (Hamann et al, 2005).…”

Molecular Characterization and Expression Pattern of Na⁺-K⁺-2Cl^- Cotransporter 2 (NKCC2) in the Intestine of Starry Flounder Platichthys stellatus after Bacterial Challenge

“…Other teleosts NKCC2s are expressed in several tissues, although distribution is not widespread. For example, NKCC2 is preferentially expressed in the intestine and kidney of the marine medaka, O. dancena (Kang et al, 2010), whereas NKCC2 is mainly expressed in the gastrointestinal tract and skeletal muscle and is abundant in the intestine, followed by the gill, esophagus, and stomach of SWtransferred Japanese eel and tilapia (Watanabe et al, 2011;Li et al, 2014). NKCC2 expression in mammals is restricted to the kidney, stomach, and intestine (e.g., jejunum and distal colon) at similar levels (Xue et al, 2009).…”

“…NKCC2 expression in mammals is restricted to the kidney, stomach, and intestine (e.g., jejunum and distal colon) at similar levels (Xue et al, 2009). In contrast, NKCC2s show somewhat different expression patterns in European and Japanese eels, in which NKCC2β expression levels are markedly higher in the anterior and posterior intestines, followed by the rectum (Cutler and Cramb, 2008;Watanabe et al, 2011). The highest expression level in olive flounder is in the posterior intestine .…”

“…In addition, a duplicated pair of NKCC2 isoforms (NKCC2α and NKCC2β) has been identified in several teleosts, and they are expressed in different tissues and organs (Cutler and Cramb, 2008;Hiroi et al, 2008;Watanabe et al, 2011). For example, NKCC2α mRNA is expressed only in the renal tissue of European eel, whereas NKCC2β expression is detected in the intestine and urinary bladder.…”

Optimizing de novo transcriptome assembly and extending genomic resources for striped catfish (Pangasianodon hypophthalmus)

“…NKCC also plays a significant role in the Cl − secretion pathway in European eel (Anguilla anguilla) (Cutler and Cramb, 2002), killifish (Scott et al, 2004) and striped bass (Morone saxatilis) (Tipsmark et al, 2004), and in some salmonids Salvelinus namaycush, Salvelinus fontinalis and S. salar (Hiroi and McCormick, 2007) after transfer to sea water. The absorptive isoform of NKCC1, NKCC2 is believed to play an important role in water reabsorption in the intestine, where it acts as an Na + uptake transporter for Na + to enter the enterocyte (or intestinal absorptive cells) (Watanabe et al, 2011). Cystic fibrosis transmembrane conductance regulator (CFTR) is another candidate gene identified in the current study that may enhance osmoregulatory capacity in P. hypophthalmus (Hwang and Lee, 2007).…”