title: A Chinese hamster cDNA encoding a protein essential for phosphatidylserine synthase I activity.
abstract: A phosphatidylserine-auxotrophic mutant of cultured Chinese hamster ovary (CHO) cells, PSA-3, is defective in phosphatidylserine synthase I activity. Transfection of PSA-3 cells with a cDNA expression library of CHO-K1 (the parent of PSA-3) yielded a phosphatidylserine-prototrophic transformant with normal phosphatidylserine synthase I activity. Using a cDNA segment retrieved from the transformant as a probe, a cDNA clone (pssA) responsible for phosphatidylserine prototrophy was isolated from the original cDNA library by colony filter hybridization. Introduction of the pssA cDNA into PSA-3 cells restored the phosphatidylserine content, and the resultant transformant exhibited 15-fold higher specific phosphatidylserine synthase I activity than CHO-K1 cells. The nucleotide sequence of the pssA cDNA contained a single long open reading frame capable of encoding a protein of 471 amino acid residues with several putative membrane-spanning domains. Our results indicated that the pssA cDNA encodes an integral membrane protein essential for phosphatidylserine synthase I activity.
authors.affiliation: Department of Chemistry, National Institute of Health, Tokyo, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Kuge
authors.forename: M
authors.initials: M
authors.lastname: Nishijima
authors.forename: Y
authors.initials: Y
authors.lastname: Akamatsu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002455:Cell Division / Q000187:drug effects; D003001:Cloning, Molecular; D003360:Cosmids; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D019884:Nitrogenous Group Transferases; D010718:Phosphatidylserines / Q000096:biosynthesis* / Q000494:pharmacology; D011487:Protein Conformation; D015183:Restriction Mapping; D012694:Serine / Q000378:metabolism; D014166:Transferases / Q000235:genetics* / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D010718:Phosphatidylserines; D012694:Serine; D004247:DNA; D014166:Transferases; D019884:Nitrogenous Group Transferases; C022370:phospholipid serine base exchange enzyme