The expression of IV6 beta[Gal beta 1-4(Fuc alpha 1-3)GlcNAc]-Gb5Cer in mouse kidney is controlled by the Gsl-5 gene through regulation of UDP-GlcNAc:Gb5Cer beta 1-6N-acetylglucosaminyltransferase activity.

We reported the polymorphic expression of GL-Y (IV6 beta[Gal beta 1-4(Fuc alpha 1-3)GlcNAc]-Gb5Cer in kidneys of inbred strains of mice in previous papers [J. Biochem. 101, 553-562 and 563-568 (1987)]. DBA/2 mice express a large amount of GL-X (Gb5Cer), but not GL-Y, in their kidneys, because of a defect on a single autosomal gene (Gsl-5). This suggested that DBA/2 mice lack the ability to transfer GlcNAc onto the C-6 position of GalNAc of Gb5Cer or GL-X. In this study, we characterized UDP-GlcNAc:GL-X beta 1-6N-acetylglucosaminyltransferase (beta 1-6GlcNAc transferase) in the microsomal fraction of mouse kidney. Maximum activity was detected with an incubation mixture containing sodium cacodylate buffer (pH 6.4), 0.1% Zwittergent 3-16 and 1 mM EDTA. Divalent cations were not required. The apparent Km values for UDP-GlcNAc and GL-X were 0.42 and 0.12 mM, respectively. The product of the enzymatic reaction was identified as IV6 beta GlcNAc-Gb5Cer by means of 1H-NMR spectroscopy and permethylation analyses. Then, we measured the beta 1-6GlcNAc transferase activity in the microsomal fractions of kidneys of inbred strains of mice and progeny obtained on mating. WHT/Ht, C57BL/10, BALB/c, and C3H/He mice, which express GL-Y in their kidneys, exhibited detectable amounts of activity, whereas CBA and DBA/2 mice, which do not express GL-Y, did not exhibit detectable activity.(ABSTRACT TRUNCATED AT 250 WORDS)