Nuclear inheritance of a gene affecting mitochondrial gene expression.
Due to a deficiency in mitochondrial protein synthesis, Chinese hamster lung (CHL) cell mutant Gal- 32 does not grow in galactose or fructose. This report examines the nuclear or cytoplasmic inheritance of this single, recessive mutation. In a control experiment, fusion of Gal+TGSTK- cells with Gal- 32TGRTK+ cells resulted in tetraploid hybrids (as verified by karyotyping) that were selected in hypoxanthine/aminopterin/thymidine medium. The majority (2/3) of the control hybrids grew in galactose as expected since Gal+ is dominant over Gal-. Fusion of Rhodamine 6-G treated Gal+TGSTK- cells with Gal- 32TGRTK+ cells resulted in Rhodamine 6-G-tetraploid hybrids that were selected in hypoxanthine/aminopterin/thymidine medium. The majority (7/12) of the Rhodamine 6-G-hybrids grew in galactose as expected for a nuclearly encoded gene considering that Rhodamine 6-G interferes with transmission of mtDNA but not nuclear DNA. Therefore, these results are compelling in their demonstration of the nuclear origin of the Gal- 32 mutation.
Sherif
Z A
ZA
Howard University College of Medicine, Department of Biochemistry and Molecular Biology, Washington, D.C. 20059, USA.
Jefferson
L M
LM
Whitfield-Broome
C D
CD
D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics*; D006224:Cricetinae; D004247:DNA / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005690:Galactose / Q000235:genetics*; D008928:Mitochondria / Q000235:genetics*; D009154:Mutation
D004272:DNA, Mitochondrial; D004247:DNA; D005690:Galactose