Abnormal growth induced by expression of HBsAg in the secretion pathway of S. cerevisiae pep4 mutants.
The toxicity of HBsAg in the secretion pathway of pep4 strains can be progressively reduced in modified SD media containing lower concentrations of ammonium sulphate. A procedure, combining a reduction of ammonium sulphate concentration in SD media with the disruption of the PEP4 gene of the host strain, was developed to enrich transformants which are not inhibited by HBsAg expressed in the secretion pathway. Abnormal growth of these non-inhibited transformants is characterized by the enlargement of cell morphology, a transition to pseudohyphal-like growth in nitrogen-starved media, an increase in HBsAg particle production, and the enhancement of growth rate in liquid media. This suggests a new approach to overcoming the toxicity of heterologous protein in the yeast secretion pathway.
Chen
D C
DC
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China.
Chuang
L T
LT
Chen
W P
WP
Kuo
T T
TT
D000595:Amino Acid Sequence; D000645:Ammonium Sulfate / Q000494:pharmacology; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D003470:Culture Media; D005656:Fungal Proteins / Q000378:metabolism*; D005822:Genetic Vectors; D006514:Hepatitis B Surface Antigens / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D014170:Transformation, Genetic
D003470:Culture Media; D005656:Fungal Proteins; D006514:Hepatitis B Surface Antigens; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C022325:aspartic proteinase A; C499267:PEP4 protein, S cerevisiae; D016282:Aspartic Acid Endopeptidases; D000645:Ammonium Sulfate