Selection of a lysine-resistant CHO-K1 mutant with reduced amino acid transport through multiple systems.
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.
DeBusk
W E
WE
Department of Anatomy, School of Medicine, University of Utah, Salt Lake City 84132.
Ash
J F
JF
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000235:genetics; D016466:CHO Cells; D002455:Cell Division; D003001:Cloning, Molecular; D006224:Cricetinae; D004351:Drug Resistance / Q000235:genetics; D007700:Kinetics; D008239:Lysine / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation
D000596:Amino Acids; D008239:Lysine