Molecular cloning and characterization of the pig secretor type alpha 1,2fucosyltransferase (FUT2)

The existence of at least two distinct alpha 1,2fucosyltransferases has bee n postulated for many years, and recently confirmed in humans with the clon ing of the human and rabbit secretor type alpha 1,2fucosyltransferase. We n ow describe the cloning and analysis of PFUT2, the pig secretor type al,2fu cosyltransferase, which shows a high level of amino acid identity with prev iously cloned alpha 1,2fucosyltransferases, but more so with human and rabb it FUT2. Expression of PFUT2 in COS cells showed cell surface staining for H substance with UEAI lectin and anti-H monoclonal antibody, but not for A blood group substance. Kinetic studies were consistent with PFUT2 having a preference for type 1 and type 3 accepters, as do the human and rabbit homo logues, in contrast re PFUT1 which shows a preference for type 2 substrates . Like HuFUT1 and PFUT1, PFUT2 was able to dominate over the pig alpha 1,3 galactosyltransferase in coexpression studies in COS cells and give prefere ntial expression of H substance and reduced expression of Gal alpha(1,3)Gal . Cotransfection studies demonstrate that a combination of FUT1 and FUT2 cD NAs has an additive effect in suppressing expression of Gal alpha(1,3)Gal.