Rapid selection using G418 of high copy number transformants of Pichia pastoris for high-level foreign gene expression

Scorer, C. A., Clare, J. J., McCombie, W. R., Romanos, M. A., Sreekrishna, K. (1994) Rapid selection using G418 of high copy number transformants of Pichia pastoris for high-level foreign gene expression. Nature Biotechnology, 12 (2). pp. 181-184. ISSN 10870156 (ISSN)

URL: http://www.ncbi.nlm.nih.gov/pubmed/7764433

Abstract

Pichia postoris is a methylotrophic yeast increasingly important in the production of therapeutic proteins. Expression vectors are based on the methanol-inducible AOX1 promoter and are integrated into the host chromosome. In most cases high copy number integration has been shown to be important for high-level expression. Since this occurs at low frequency during transformation, we previously used DNA dot blot screens to identify suitable clones. In this paper we report the use of vectors containing the Tn903 kanr gene conferring G418-resistance. Initial experiments demonstrated that copy number showed a tight correlation with drug-resistance. Using a G418 growth inhibition screen, we readily isolated a series of transformants, containing progressively increasing numbers (1 to 12) of a vector expressing HIV-1 ENV, which we used to examine the relationship between copy number and foreign mRNA levels. Northern blot analysis indicated that ENV mRNA levels from a single-copy clone were nearly as high as AOX1 mRNA, and increased progressively with increasing copy number so as to greatly exceed AOX1 mRNA. We have also developed protocols for the selection, using G418, of high copy number transformants following spheroplast transformation or electroporation. We anticipate that these protocols will simplify the use of Pichia as a biotechnological tool.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing
bioinformatics > genomics and proteomics
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > copy number variants
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > gene expression
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function
organism description > yeast
CSHL Authors:
Communities: CSHL labs > McCombie lab
Depositing User: Matt Covey
Date Deposited: 23 Apr 2013 16:48
Last Modified: 23 Apr 2013 16:48
Related URLs:
URI: http://repository.cshl.edu/id/eprint/28239

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