Abstract: Methods for producing a heterologous protein or polypeptide are disclosed. A preferred method utilizes a fungal cell carrying a defect in a gene whose product is required for the addition of outer chain oligosaccharide moieties to glycoproteins, the cell transformed with a first DNA construct comprising a regulated promoter followed downstream by a DNA sequence which complements the defect, and a second DNA construct comprising a second promoter followed downstream by a DNA sequence encoding a secretion signal and a DNA sequence encoding a heterologous protein or polypeptide. A yeast cell having a Mnn9.sup.- phenotype and capable of producing colonies of normal morphologies in the absence of osmotic stabilization is also disclosed.

Abstract: Methods for producing heterologous proteins in a host organism whereby the proteins are processed through the secretory pathway of the host are provided. Secretion is achieved by transforming a host organism with a DNA construct comprising a transcriptional promoter operably linked to DNA sequences encoding a signal peptide, at least a portion of the BAR1 C-terminal domain capable of directing the export of heterologous proteins and a heterologous protein or polypeptide. DNA constructs and transformants are also provided wherein the DNA sequence encoding at least a portion of the C-terminal domain of BAR1 capable of directing the export of heterologous proteins further comprises a DNA sequence encoding a proteolytic cleavage site operably linked to the DNA sequence encoding a heterologous protein.