Korean J Anat.  2005 Apr;38(2):189-198.

Cloning and Expression of Sodium-Bicarbonate Cotransporter Isoform in Rat

• Yoon HD
• Cho HJ
• Chung HY
• Nam KI
• Bae CS
• Kim BY
• Park SS
• Ahn KY

Abstract

The potassium depletion has remarkable and opposite effect on kidney and body growth and has affected the expression of the several ion transporters. Previously, Ahn et al. have reported that HK alpha 1 and 2 subunit gene were upregulated in the hypokalemic rat kidney. To clone the unreported genes expressed in potassium deficiency, differential display PCR-based cloning strategy was used in normal and potassium-depleted rat kidney and a novel gene was isolated. Sequence analysis with blast search program identified a cDNA clone encoding an isoform of kidney sodium bicarbonate cotransporter-1. The tissue and cellular expression pattern of this gene were investigated with Northern analyses and in situ hybridization histochemistry (ISH) in normal and hypokalemic rats. This novel transcript was highly expressed in kidney and brain and at lower levels in distal colon, urinary bladder, and heart but not in salivary gland, stomach, liver, and lung in normal rat. In potassium-depleted rat, this transcript was upregulated in kidney, brain, and distal colon. By ISH, cellular distribution of this gene was highly expressed in S3 segment of proximal tubule, distal convoluted tubule, and cortical collecting duct of kidney and lower third of intestinal glands of distal colon but at lower levels in cortical and medullary thick ascending limb and medullary collecting duct of kidney and middle third of intestinal glands of distal colon. From these results, this candidate gene may play an important role in HCO3-transport by these organs during potassium depletion.

Keyword

Hypokalemia; NBC-1; DD-PCR; Kidney; Isoform

MeSH Terms

Animals
Brain
Clone Cells*
Cloning, Organism*
Colon
DNA, Complementary
Extremities
Heart
Hypokalemia
In Situ Hybridization
Intestinal Mucosa
Ion Transport
Kidney
Liver
Lung
Potassium
Potassium Deficiency
Rats*
Salivary Glands
Sequence Analysis
Sodium Bicarbonate
Sodium-Bicarbonate Symporters*
Stomach
Urinary Bladder
DNA, Complementary
Potassium
Sodium Bicarbonate
Sodium-Bicarbonate Symporters