Amplification and high-level expression of a cDNA for human granulocyte-macrophage colony-stimulating factor in human lymphoblastoid Namalwa cells.
We have achieved high-level expression of human granulocyte-macrophage colony-stimulating factor (GM-CSF) in human lymphoblastoid Namalwa cells by introducing and subsequently amplifying an expression vector encoding human GM-CSF and mouse dihydrofolate reductase (DHFR). Transformants expressing elevated levels of both GM-CSF and DHFR were selected by a step-wise increase in the concentration of methotrexate (MTX). Several cell lines resistant in 800 nM MTX have been established that express GM-CSF at a rate of 10-20 micrograms/10(6) cells/day. The amplified genes are integrated and stably maintained in the chromosomes of these cell lines. Analysis of the GM-CSF produced in the amplified Namalwa cells revealed that the molecular-size distribution due to varied degrees of glycosylation was similar to that observed in the naturally-occurring molecules.
Okamoto
M
M
Biotechnology Laboratory, Takarazuka Research Center, Sumitomo Chemical Co., Ltd., Hyogo, Japan.
Nakayama
C
C
Nakai
M
M
Yanagi
H
H
D003001:Cloning, Molecular; D003115:Colony-Stimulating Factors / Q000096:biosynthesis / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D007945:Leukemia, Lymphoid / Q000235:genetics*; D014407:Tumor Cells, Cultured
D003115:Colony-Stimulating Factors; D006133:Growth Substances; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004247:DNA