DeBusk WE, Ash JF. Selection of a lysine-resistant CHO-K1 mutant with reduced amino acid transport through multiple systems.
SOMATIC CELL AND MOLECULAR GENETICS 1993;
19:331-45. [PMID:
8211377 DOI:
10.1007/bf01232746]
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Abstract
High levels of L-lysine were used to select for resistant variants of Chinese hamster ovary (CHO-K1) cells. Surviving colonies were screened for altered lysine transport and two with reduced uptake were picked. Clone CH-Kr, derived from the more severely affected colony, was analyzed in detail. In starved cells the Vmax of lysine uptake in CH-Kr was half that of CHO while Km was unaltered. The intracellular pool of lysine, a substrate of cationic amino acid transport system y+, was significantly lower in CH-Kr. However, transport and pools of other amino acids, which are not substrates of y+, were also reduced in CH-Kr, as was the internal sodium concentration, while hexose import was increased. It appears that the mutation in CH-Kr is pleiotropic, affecting some general aspects of amino acid transport.
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