TRANSFECTION OF THE KETOGENIC MITOCHONDRIAL 3-HYDROXY-3-METHYLGLUTARYL-COENZYME-A SYNTHASE CDNA INTO MEV-1 CELLS CORRECTS THEIR AUXOTROPHY FOR MEVALONATE
Ja. Ortiz et al., TRANSFECTION OF THE KETOGENIC MITOCHONDRIAL 3-HYDROXY-3-METHYLGLUTARYL-COENZYME-A SYNTHASE CDNA INTO MEV-1 CELLS CORRECTS THEIR AUXOTROPHY FOR MEVALONATE, The Journal of biological chemistry, 269(46), 1994, pp. 28523-28526
A somatic cell mutant of the Chinese hamster ovary (CHO)-K1 (called Me
v-1), auxotrophic for mevalonate by virtue of a complete lack of detec
table cytosolic 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) syntha
se activity, was transfected with a plasmid containing the cDNA for ke
togenic mitochondrial HMG-CoA synthase under the control of SV40 early
promoter. The resulting stable cell line (Mev-SM) was able to grow in
the absence of mevalonate. Analysis by Western blot showed that the n
ew cell line strongly expressed mitochondrial HMG-CoA synthase protein
. Immunocytochemical studies using specific antibodies against mitocho
ndrial HMG-CoA synthase showed that the protein was located exclusivel
y inside the mitochondria. The prototroph cell line Mev-SM can incorpo
rate labeled ac etate into cholesterol in the absence of mevalonate. T
hese results show that the new cell, line may circumvent the lack of c
ytosolic HMG-CoA synthase activity by producing cholesterol-convertibl
e HMG-CoA inside the mitochondria.