Expression of Normal and Mutant Pyruvate Dehydrogenase Complex E1α cDNAs in Cultured Human Lymphoblasts,

Transfection of PDH E-1 alpha cDNAs into human normal (3781) and PDH-deficient (4787) lymphoblast cell lines was performed to study the expression of different E-1 alpha cDNAs. Transfection of normal human E-1 alpha cDNA into a severely PDH-deficient cell line with 10% residual activity resulted in a fivefold increase in residual PDR complex activity. Transfection of the normal cDNA into the normal cell line did not affect the residual enzyme activity, Transfection of three known human PDH E-1 alpha mutations (A875T, C787G, and a 13-bp insertion at nucleotide 981) into the normal cell line resulted in a decrease of PDH complex activity, Expression of these same mutations in the deficient cell line resulted in an increase of PDH complex activity, with the C787G mutation causing the greatest increase in enzyme activity. The increase in activity seen with A875T expressed in the mutant cell line suggested that interallelic complementation had occurred. (C) 1999 Academic Press.