Voelcker Academy
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Yun Liang

Regulation of Mammalian Mitochondrial DNA Copy Number

Yun Liang

Mentor: Dr. Yidong Bai

Mitochondria are ubiquitous organelles in the eukaryotic cells, essential for the creation of ATP via oxidative phosphorylation. In addition, mitochondria play an important role in the signal transduction of cell proliferation and cell apoptosis. Among many of their uniqueness, mitochondria posses their own set of genomes with maternal inheritance patterns. These genomes in humans have a circular structure of double stranded DNA with 16.6 kb. Much of their genomes are polyploidy, having up to several thousands of copies in each cell. Moreover, replication and transcription of mtDNA are coupled with unique methods that are independent of the cell cycle. To better understand how the mtDNA copy number control is regulated, we will observe mtDNA replication and turnover using imaging techniques, developed from immunocytochemistry, to visualize changes in mitochondrial nucleoids structure in the artificial cycle produced by exposure of mtDNA from mouse cells to ethidium bromide. We hypothesized that mtDNA copy number control is highly regulated, depending on the type of tissue, as supported by the higher ratio of mtDNA to nuclear DNA found in cells that engage in higher oxidative phosphorylation activities, such as muscle and heart cells.Since mtDNA copy number can affect the efficiency of cellular processes which will affect the overall health of the organism, understanding the regulations of mtDNA copy number control and how changes in these regulations affect the organism are critical in gaining a deeper knowledge of various diseases and aging. Therefore, with better comprehension, we could devise better treatment for mitochondrial diseases such as metabolic disorders and aging.

Collaborators: Laura Montier, Jianhong Deng, Deborah Holstein and James Lechleiter