Methods for reducing or eliminating α-mannosidase resistant glycans for the production of glycoproteins
The present invention provides methods to reduce or eliminate α-mannosidase resistant glycans on glycoproteins in yeast. The reduction or elimination of α-mannosidase resistant glycans on glycoproteins results from the disruption of the newly isolated P. pastoris AMR2 gene encoding β1,2-mannosyltransferase. The present invention also discloses novel genes, polypeptides, antibodies, vectors and host cells relating to α-mannosidase resistance on glycans.
1. A modified Pichia pastoris host cell characterized in that the host cell has been modified to reduce expression of a functional gene product of a nucleic acid sequence encoding a polypeptide having the amino acid sequence set forth in SEQ ID NO:12.
2. The modified host cell of claim 1 wherein said modified host cell comprises a disruption or deletion in the nucleic acid sequence encoding a polypeptide having the amino acid sequence set forth in SEQ ID NO:12.
3. The host cell of claim 1 , wherein the host cell further comprises deletion of a functional gene product encoding an alpha-1,6-mannosyltransferase activity.
4. The host cell of claim 1 , wherein the host cell further comprises deletion of a functional gene product encoding mannosylphosphate transferase activity.
5. A modified Pichia pastoris host cell characterized in that the host cell has been modified to reduce expression of a β-mannosyltransferase activity.
6. The modified host cell of claim 5 wherein said modified host cell comprises a disruption or deletion in the nucleic acid sequence encoding the β-mannosyltransferase activity.
7. The host cell of claim 5 , wherein the host cell further comprises deletion of a functional gene product encoding an alpha-1,6-mannosyltransferase activity.
8. The host cell of claim 5 , wherein the host cell further comprises deletion of a functional gene product encoding mannosylphosphate transferase activity.