Expression Patterns of Two Genes for the Delta-Subunit of Mitochondrial F sub(1)-ATP Synthase from Sweet Potato in Transgenic Tobacco Plants and Cells

• Published in: Plant and cell physiology Vol. 40; no. 8; pp. 866 - 873
• Main Authors: Maeo, K, Morikami, A, Soga, M, Imanishi, S, Nakamura, K
• Format: Journal Article
• Language: English
• Published: 01.08.1999
• Subjects: F1^d-1 gene; F1^d-2 gene; F1d-1 gene; F1d-2 gene; Ipomoea batatas; Nicotiana tabacum; oligomycin
• ISSN: 0032-0781

Two nuclear genes, F sub(1) delta -1 and F sub(1) delta -2, coding for the delta -subunit of mitochondrial F sub(1)-ATP synthase, which corresponds to oligomycin-sensitivity conferring protein in animal and yeast mitochondria, were isolated from sweet potato. The gene for the delta -subunit was composed of 6 exons and these two genes shared high sequence similarities to each other not only in exons but also in introns and in the 5'-upstream regions. However, the 5'-upstream regions of F sub(1) delta -1 and F sub(1) delta -2 were distinguishable by the presence of novel sequences, designated Ins-1 and Ins-2, respectively. Ins-1 and Ins-2 contained a terminal direct repeat of 10 bp and 12 bp, respectively, and various forms of repeat sequences. The promoter fusion of both F sub(1) delta -1 and F sub(1) delta -2 with the GUS coding sequence gave expression of GUS activity in transformed tobacco BY-2 cells, although the levels of GUS activity and the patterns of expression during the growth of cells were different between the two. In transgenic tobacco plants, the two fusion genes showed similar levels of expression in leaves and stems, while F sub(1) delta -2:GUS gave significantly higher levels of expression in roots than F sub(1) delta -1:GUS. Deletion of Ins-1 from the 5'-upstream region of F sub(1) delta -1:GUS did not affect the expression of the fusion gene in various organs of transgenic plants. However, it caused significant enhancement of expression in transformed tobacco BY-2 cells.