| 摘要 |
The present invention provides formaldehyde dehydrogenase genes (FLD) from methylotrophic yeasts. The FLD structural genes confer resistance to formaldehyde and are therefore useful as a selectable marker in methylotroph ic yeasts. The FLD promoter sequences are strongly and independently induced by either methanol as sole carbon source (with ammonium sulfate as nitrogen source) or methylamine as sole nitrogen source (with glucose as carbon source). Induction under either methanol, methylamine or both provides level s of heterologous gene expression comparable to those obtained with the common ly used alcohol oxidase I gene promoter (PAOX1). The FLD promoter of Pichia pastoris (PFLD1) is an attractive alternative to PAOX1 for expression of foreign genes in P. pastoris, allowing regulation by carbon (methanol) or nitrogen (methylamine) source within the same expression strain. Yeast strains, expression cassettes, expression vectors, and host cells comprising an FLD gene promoter and 3' termination sequence are also provided.
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