title: New mutations and phenotypes associated with glutamate and aspartate transport in Chinese hamster ovary (CHO-K1) cells.
abstract: Two new Chinese hamster ovary cell (CHO-K1) mutants lacking amino acid transport System X-AG activity were isolated by [3H]aspartate suicide selection. These null mutants, Dd-B6 and Dd-B7, were analyzed by somatic cell hybridization, along with previously described partial-function mutants, Ed-A1 and Ed-B8. With respect to System X-AG activity, all four mutations fell into a single complementation group. By quantitative assay, the mutations in Ed-A1 and Ed-B8 behaved as simple recessives in fusions with wild type cells, while those in Dd-B6 and Dd-B7 were codominant. We have discovered that Ed-A1 and Ed-B8 are highly permeable to small neutral molecules. This high permeability phenotype was dominant to wild-type. Northern, Southern, and Western analyses indicated that System X-AG in CHO is not closely related to any of the three well characterized glutamate transporters represented by GLT-1, EAACI or GLAST.
authors.affiliation: Department of Neurobiology and Anatomy, School of Medicine, University of Utah, Salt Lake City 84132, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Igo
authors.forename: J F
authors.initials: JF
authors.lastname: Ash
mesh_terms: D027322:Amino Acid Transport System X-AG; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D001692:Biological Transport; D001923:Brain Chemistry; D016466:CHO Cells; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D002462:Cell Membrane / Q000737:chemistry; D002463:Cell Membrane Permeability; D006224:Cricetinae; D027341:Excitatory Amino Acid Transporter 1; D005816:Genetic Complementation Test; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics; D006822:Hybrid Cells; D007700:Kinetics; D051379:Mice; D009154:Mutation; D010641:Phenotype; D012333:RNA, Messenger / Q000032:analysis; D027981:Symporters; D014508:Urea / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D027322:Amino Acid Transport System X-AG; D002352:Carrier Proteins; D027341:Excitatory Amino Acid Transporter 1; D050491:Glutamate Plasma Membrane Transport Proteins; D006023:Glycoproteins; D012333:RNA, Messenger; C493393:Slc1a3 protein, mouse; D027981:Symporters; D014867:Water; D001224:Aspartic Acid; D018698:Glutamic Acid; D014508:Urea; D005990:Glycerol