A MUTATION LINKED TO ELEVATED GLUCOSE IN THE URINE

(WITHOUT DIABETES)

Nutrition and Gene ExpressionJan 30, 2014

FUNCTION OF KIDNEY GLOMERULUS:Fluid from the artery forms the glomerular

filtrate, and then many components arereabsorbed back to the bloodstream.

ARTERY

VEIN

URINE

Fluid from the plasma:glomerular filtratecontains glucose

It is generally accepted that two Na+ glucose cotransporters(SGLT) exist in the apical membrane of the convolutedtubule (Brown 2000; Wright 2001).

SGLT2, a low-affinity high-capacity transporter localized in the early proximal tubule as shown by in situ hybridization, is responsible for reabsorption of the bulk of the filtered glucose (Kanai et al. 1994; You et al. 1995). SGLT1 is located in the late proximal tubule, where it reabsorbs the remainder of the filtered glucose not reabsorbed in the early proximal tubule (Lee et al. 1994).

NORMAL

MUTATED

CHANGE IN TGG CODON

TGG on DNA IS TRANSCRIBED TO UGG = Tryptophan

TGA on DNA IS TRANSCRIBED TO UGA = STOP

This is a good time to discuss the “coding strand” and thetemplate strand (additional details on the board).

To save space, we don’t need to show the complete double-strand.

If we write ACGTCTGG

Then the other strand must be TGCAGACC

The top strand usually written is the “coding strand”. The other strand,NOT written, used to make the RNA, is called the “template strand.

FOR EXAMPLE, IF CODING IS TGG, TEMPLATE IS ACC,WHICH IS READ INTO RNA AS UGG.