J. Biol. Chem., Vol. 265, Issue 12, 6525-6527, Apr, 1990
Novel regulatory enhancer in the nuclear gene of the human mitochondrial ATP synthase beta-subunit
H Tomura, H Endo, Y Kagawa and S Ohta
Department of Biochemistry, Jichi Medical School, Tochigi-ken, Japan.
The system coordinating expressions of nuclear coded mitochondrial proteins
was investigated by examination of the 5'-flanking region of the human
mitochondrial ATP synthase beta-subunit gene. The promoter activity was
measured by a transient expression of a chloramphenicol acetyltransferase
(CAT) gene connected with various 5'-deletion mutants of the 5'-flanking
region. In this experiment, at least two regions enhanced this promoter
activity and at least one region repressed it. In one of the enhancing
regions, a consensus sequence was found for the genes of other
mitochondrial proteins such as those for cytochrome c1 (Suzuki, H.,
Hosokawa, Y., Nishikimi, M., and Ozawa, T. (1989) J. Biol. Chem. 264,
1368-1374) and the pyruvate dehydrogenase alpha-subunit (Maragos, C.,
Hutchison, W. M., Hayasaka, K., Brown, G. K., and Dahl, H.-H. M. (1989) J.
Biol. Chem. 264, 12294-12298; Ohta, S., Endo, H., Matsuda, K., and Kagawa,
Y. (1989) Ann. N. Y. Acad. Sci. 573, 458-460). The characteristics of this
enhancing element were examined by introducing a synthetic oligonucleotide
element into the CAT plasmid with a deleted enhancing element. The
resulting plasmid showed full recovery of promoter activity, and this
activity was independent of the orientation or location of the insert.
Therefore, this is an enhancer that may be common to the nuclear genes of
some mitochondrial proteins involved in energy transduction.