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Methylotrophic Yeast Hansenula Polymorpha (methylotrophic + yeast_hansenula_polymorpha)
Selected AbstractsReprogramming Hansenula polymorpha for penicillin production: expression of the Penicillium chrysogenum pcl geneFEMS YEAST RESEARCH, Issue 7 2007Loknath Gidijala Abstract We aim to introduce the penicillin biosynthetic pathway into the methylotrophic yeast Hansenula polymorpha. To allow simultaneous expression of the multiple genes of the penicillin biosynthetic pathway, additional markers were required. To this end, we constructed a novel host,vector system based on methionine auxotrophy and the H. polymorpha MET6 gene, which encodes a putative cystathionine ,-lyase. With this new host,vector system, the Penicillium chrysogenum pcl gene, encoding peroxisomal phenylacetyl-CoA ligase (PCL), was expressed in H. polymorpha. PCL has a potential C-terminal peroxisomal targeting signal type 1 (PTS1). Our data demonstrate that a green fluorescent protein,PCL fusion protein has a dual location in the heterologous host in the cytosol and in peroxisomes. Mutation of the PTS1 of PCL (SKI-COOH) to SKL-COOH restored sorting of the fusion protein to peroxisomes only. Additionally, we demonstrate that peroxisomal PCL,SKL produced in H. polymorpha displays normal enzymatic activities. [source] Increase of calnexin gene dosage boosts the secretion of heterologous proteins by Hansenula polymorphaFEMS YEAST RESEARCH, Issue 7 2007Jens Klabunde Abstract The type I membrane protein calnexin is a conserved key component of the quality control mechanism in the endoplasmic reticulum. It functions as a molecular chaperone that monitors the folding state of nascent polypeptides entering the endoplasmic reticulum. Calnexin also behaves as a lectin, as its chaperoning activity involves binding of oligosaccharide moieties present on newly imported glycoproteins. We isolated the calnexin gene (HpCNE1) from the methylotrophic yeast Hansenula polymorpha, and used HpCNE1 expression plasmids for supertransformation of H. polymorpha strains secreting target proteins of biotechnological interest. The elevated dosage of HpCNE1 enhanced secretion of the four proteins tested: three glycoproteins and one unglycosylated product. Secretion of bacterial alginate epimerase AlgE1 was increased threefold on average, and secretion of both human interferon-, and fungal consensus phytase twofold. With phytase and AlgE1 this improvement was all the more remarkable, as the secretion level was already high in the original strains (g L,1 range). The same approach improved secretion of human serum albumin, which lacks N-linked glycans, about twofold. Glycosylation of the pro-MF,1 leader may account for the effect of calnexin in this case. Our results argue that cooverexpression of calnexin can serve as a generally applicable tool for enhancing the secretion of all types of heterologous protein by H. polymorpha. [source] GSH2, a gene encoding ,-glutamylcysteine synthetase in the methylotrophic yeast Hansenula polymorphaFEMS YEAST RESEARCH, Issue 3 2002Vira M Ubiyvovk Abstract The GSH2 gene, encoding Hansenula polymorpha,-glutamylcysteine synthetase, was cloned by functional complementation of a glutathione (GSH)-deficient gsh2 mutant of H. polymorpha. The gene was isolated as a 4.3-kb XbaI fragment that was capable of restoring GSH synthesis, heavy-metal resistance and cell proliferation when introduced into gsh2 mutant cells. It possesses 53% identical and 69% similar amino acids compared with the Candida albicans homologue (Gcs1p). In comparison to the Saccharomyces cerevisiae homologue (Gsh1p), it possesses 47% identical and 61% similar amino acids. The GSH2 sequence appears in the GenBank database under accession No. AF435121. [source] Glycoengineering of the methylotrophic yeast Hansenula polymorpha for the production of glycoproteins with trimannosyl core N -glycan by blocking core oligosaccharide assemblyBIOTECHNOLOGY JOURNAL, Issue 5 2008Doo-Byoung Oh Abstract The initial lipid-linked oligosaccharide Glc3Man9GlcNAc2 -dolichyl pyrophosphate (Dol-PP) for N -glycan is synthesized and assembled at the membrane of the endoplasmic reticulum (ER) and subsequently transferred to a nascent polypeptide by the oligosaccharide transferase complex. We have identified an ALG3 homolog (HpALG3) coding for a dolichyl-phosphate-mannose dependent ,-1,3-mannosyltransferase in the methylotrophic yeast Hansenula polymorpha. The detailed analysis of glycan structure by linkage-specific mannosidase digestion showed that HpALG3 is responsible for the conversion of Man5GlcNAc2 -Dol-PP to Man6GlcNAc2 -Dol-PP, the first step to attach a mannose to the lipid-linked oligosaccharide in the ER. The N -glycosylation pathway of H. polymorpha has been remodeled by deleting the HpALG3 gene in the Hpoch1 null mutant strain blocked in the yeast-specific outer mannose chain synthesis and by introducing an ER-targeted Aspergillus saitoi , -1,2-mannosidase gene. This glycoengineered H. polymorpha strain produced glycoproteins mainly containing trimannosyl core N -glycan (Man3GlcNAc2), which is the common core backbone of various human-type N -glycans. The results demonstrate the high potential of H. polymorpha to be developed as an efficient expression system for the production of glycoproteins with humanized glycans. [source] | ||||||||||