Specialized expression of simple O-glycans along the rat kidney nephron

Glycosyltransferases can exhibit tissue-specific expression. By histochemis try glycosyltransferases and their products can be localized to specific ce ll types in organs of complex cellular composition. We have applied the Pec tin Amaranthin, having a nominal specificity for Gal beta 1,3GalNAcR and Ne u5Ac2,3Gal beta 1,3GalNAc alpha-R, and a monoclonal antibody raised against Gal beta 1,3GalNAc alpha R to examine the distribution of these simple O-g lycans in adult rat kidney. The monoclonal antibody stained ascending thin limbs of Henle, distal convoluted tubules, and collecting ducts of cortex a nd outer medulla, Remarkably, the ascending thick limb of Henle, located be tween ascending thin limb and distal convoluted tubules, was unreactive. Ho wever, Amaranthin staining was detectable in ascending thick limbs of Henle , in addition to the structures positive with the monoclonal antibody. In k idney extracts, two bands of approximately 160 kDa and >210 kDa were reacti ve with both Amaranthin and the monoclonal antibody. One band at similar to 200 kDa, and a smear at similar to 100 kDa, were reactive only with Amaran thin. Our data show that in rat kidney simple O-linked glycans are expresse d in a highly specialized manner along the renal tubule and can be detected only on a few glycoproteins, This may reflect a cell-type-specific express ion of the corresponding glycosyltransferases.