Method for Producing Recombinant Glycoproteins Having Beta1,2-Bound Xylose Residues

Abstract

A DNA molecule is provided which comprises a sequence according to SEQ ID NO: 8 having an open reading frame from base pair 227 to base pair 1831 or having at least 50% homology to the above-indicated sequence, or hybridizing with the above-indicated sequence under stringent conditions, or comprising a sequence which has degenerated to the above-indicated DNA sequence because of the genetic code, the sequence coding for a plant protein having β1,2-xylosyltransferase activity or being complementary thereto.

1 - 32 . (canceled) 
     
     
         33 . A method of producing a recombinant glycoprotein, comprising expressing the recombinant glycoprotein in a plant or plant cell in which production of an endogenous β1,2-xylosyltransferase is suppressed or completely stopped, wherein said endogenous β1,2-xylosyltransferase can be identified by sequence comparison with the β1,2-xylosyltransferase sequence according to SEQ ID NO:8 with an open reading frame from base pair 227 to base pair 1831. 
     
     
         34 . The method of claim  1 , wherein said endogenous β1,2-xylosyltransferase is identified by sequence comparison with the β1,2-xylosyltransferase sequence according to SEQ ID NO:8 with an open reading frame from base pair 227 to base pair 1831 bp the program fastDB. 
     
     
         35 . The method according to claim  1 , wherein the recombinant glycoprotein is a human protein. 
     
     
         36 . The method of claim  1 , wherein the expression of the β1,2-xylosyltransferase is suppressed or completely blocked by a knock-out mutation of the endogenous β1,2-xylosyltransferase gene in said plant or plant cell. 
     
     
         37 . The method of claim  1 , wherein the expression of the β1,2-xylosyltransferase is suppressed or completely blocked by antisense inhibition in said plant or plant cell. 
     
     
         38 . The method of claim  1 , wherein the expression of the β1,2-xylosyltransferase is suppressed or completely blocked by transfection with a polynucleotide comprising a sequence of at least 50 nucleotides that is complementary to the sequence coding for the endogenous β1,2-xylosyltransferase. 
     
     
         39 . The method of claim  1 , wherein the endogenous β1,2-xylosyltransferase activity in said plant or plant cell is less than 50% of the β1,2-xylosyltransferase occurring in natural plants or plant cells without β1,2-xylosyltransferase suppression. 
     
     
         40 . A method of producing a recombinant glycoprotein, comprising:
 (a) identifying an endogenous β1,2-xylosyltransferase in a plant or plant cell by (i) sequence comparison with the β1,2-xylosyltransferase sequence according to SEQ ID NO:8 with an open reading frame from base pair 227 to base pair 1831, and (ii) assay for β1,2-xylosyltransferase activity;   (b) suppressing or completely stopping said endogenous β1,2-xylosyltransferase production in the plant or plant cells; and   (c) expressing the recombinant glycoprotein in the plant or plant cell in which production of an endogenous β1,2-xylosyltransferase is suppressed or completely stopped.   
     
     
         41 . A method of producing a plant or plant cell with reduced or no endogenous β1,2-xylosyltransferase activity, comprising:
 (a) identifying an endogenous β1,2-xylosyltransferase by (i) sequence comparison with the β1,2-xylosyltransferase sequence according to SEQ ID NO:8 with an open reading frame from base pair 227 to base pair 1831 and (ii) assay for β1,2-xylosyltransferase activity; and 
 (b) suppressing or completely stopping said endogenous β1,2-xylosyltransferase production. 
 
     
     
         42 . The method of  claim 41 , wherein said endogenous β1,2-xylosyltransferase is identified by sequence comparison with the β1,2-xylosyltransferase sequence according to SEQ ID NO:8 with an open reading frame from base pair 227 to base pair 1831 bp the program fastDB. 
     
     
         43 . The method of  claim 41 , wherein the expression of the β1,2-xylosyltransferase is suppressed or completely blocked by a knock-out mutation of the endogenous β1,2-xylosyltransferase gene in said plant or plant cell. 
     
     
         44 . The method of  claim 41 , wherein the expression of the β1,2-xylosyltransferase is suppressed or completely blocked by antisense inhibition in said plant or plant cell. 
     
     
         45 . The method of  claim 41 , wherein the expression of the β1,2-xylosyltransferase is suppressed or completely blocked by transfection with a polynucleotide comprising a sequence of at least 50 nucleotides that is complementary to the sequence coding for the endogenous β1,2-xylosyltransferase. 
     
     
         46 . The method of  claim 41 , wherein the endogenous β1,2-xylosyltransferase activity in said plant or plant cell is less than 50% of the β1,2-xylosyltransferase occurring in natural plants or plant cells without β1,2-xylosyltransferase suppression.