Abstract: Novel genes encoding P. pastoris ARG1, ARG2, ARG3, HIS1, HIS2, HIS5 and HIS6 are disclosed. A method for inactivating alternately at least two biosynthetic pathways in a methylotrophic yeast is provided. A method for producing and selecting yeast strains characterized as being capable of genetic stable integration of heterologous sequences into the host genome using the genes involved in the biosynthetic pathways is also disclosed.

Abstract: The present invention relates to eukaryotic host cells, especially lower eukaryotic host cells, having modified oligosaccharides which may be modified further by heterologous expression of a set of glycosyltransferases, sugar and sugar nucleotide transporters to become host-strains for the production of mammalian, e.g., human therapeutic glycoproteins. The process provides an engineered host cell which can be used to express and target any desirable gene(s) involved in glycosylation. Host cells with modified lipid-linked oligosaccharides are created or selected. N-glycans made in the engineered host cells exhibit GnTIII, GnTIV, GnTV, GnT VI or GnTIX activity, which produce bisected and/or multiantennary N-glycan structures and may be modified further by heterologous expression of one or more enzymes, e.g., glycosyltransferases, sugar, sugar nucleotide transporters, to yield human-like glycoproteins.

Abstract: The present invention provides a novel lower eukaryotic host cell producing human-like glycoproteins characterized as having a terminal ?-galactose residue and essentially lacking fucose and sialic acid residues. The present invention also provides a method for catalyzing the transfer of a galactose residue from UDP-galactose onto an acceptor substrate in a recombinant lower eukaryotic host cell, which can be used as a therapeutic glycoprotein.

Abstract: The present invention relates to eukaryotic host cells having modified oligosaccharides which may be modified further by heterologous expression of a set of glycosyltransferases, sugar transporters and mannosidases to become host-strains for the production of mammalian, e.g., human therapeutic glycoproteins. The process provides an engineered host cell which can be used to express and target any desirable gene(s) involved in glycosylation. Host cells with modified lipid-linked oligosaccharides are created or selected. N-glycans made in the engineered host cells exhibit GnTIII activity, which produce bisected N-glycan structures and may be modified further by heterologous expression of one or more enzymes, e.g., glycosyltransferases, sugar transporters and mannosidases, to yield human-like glycoproteins. For the production of therapeutic proteins, this method may be adapted to engineer cell lines in which any desired glycosylation structure may be obtained.

Abstract: The present invention relates to host cells having modified lipid-linked oligosaccharides which may be modified further by heterologous expression of a set of glycosyltransferases, sugar transporters and mannosidases to become host-strains for the production of mammalian, e.g., human therapeutic glycoproteins. The process provides an engineered host cell which can be used to express and target any desirable gene(s) involved in glycosylation. Host cells with modified lipid-linked oligosaccharides are created or selected. N-glycans made in the engineered host cells have a GlcNAcMan3GlcNAc2 core structure which may then be modified further by heterologous expression of one or more enzymes, e.g., glycosyl-transferases, sugar transporters and mannosidases, to yield human-like glycoproteins. For the production of therapeutic proteins, this method may be adapted to engineer cell lines in which any desired glycosylation structure may be obtained.