Acid incubation increases NHE-3 mRNA abundance in OKP cells

Am J Physiol. 1995 Jul;269(1 Pt 1):C126-33. doi: 10.1152/ajpcell.1995.269.1.C126.

Abstract

With the use of degenerate primers based on conserved amino acid sequences in human, rat, and rabbit Na/H exchanger-3 (NHE-3), a polymerase chain reaction product was obtained from reverse-transcribed OKP (a clonal opossum kidney cell line) mRNA and used to screen an OKP cDNA library. The clone obtained predicted an amino acid sequence that was 86% identical to rat NHE-3, 33% to NHE-1, 35% to NHE-2, and 30% to NHE-4. Expression of the corresponding cRNA in Xenopus oocytes induced 22Na uptake with ethylisopropylamiloride. (EIPA) resistance similar to that of the OKP Na/H antiporter. On RNA blot, the cDNA labeled a 9.5-kb transcript whose abundance was increased 2.2-fold by 24-h incubation of OKP cells at pH 7.0 and 2.5-fold by 24-h incubation at pH 6.8. The acid-induced increase in NHE-3 mRNA was detectable at 12 h and increased further at 24 h. Incubation in acid media caused an increase in EIPA-resistant Na/H antiporter activity that preceded the increase in NHE-3 mRNA. In summary, OKP cells express an NHE-3 transcript that encodes an EIPA-resistant Na/H antiporter and is chronically regulated by acid.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acids / pharmacology*
  • Amiloride / analogs & derivatives
  • Amiloride / pharmacology
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell Line
  • Drug Resistance
  • Hydrogen-Ion Concentration
  • Kidney / cytology
  • Kidney / metabolism
  • Molecular Probes / genetics
  • Molecular Sequence Data
  • Oocytes / metabolism
  • Opossums
  • RNA, Messenger / metabolism*
  • Sodium-Hydrogen Exchanger 3
  • Sodium-Hydrogen Exchangers / genetics*
  • Sodium-Hydrogen Exchangers / metabolism
  • Xenopus laevis

Substances

  • Acids
  • Molecular Probes
  • RNA, Messenger
  • SLC9A3 protein, human
  • Slc9a3 protein, rat
  • Sodium-Hydrogen Exchanger 3
  • Sodium-Hydrogen Exchangers
  • Amiloride
  • ethylisopropylamiloride

Associated data

  • GENBANK/L42522