A Chinese hamster cDNA encoding a protein essential for phosphatidylserine synthase I activity

Osamu Kuge, Masahiro Nishijima, Yuzuru Akamatsu

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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.

Original languageEnglish
Pages (from-to)24184-24189
Number of pages6
JournalJournal of Biological Chemistry
Volume266
Issue number35
Publication statusPublished - Dec 15 1991
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Biochemistry

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