First DNA sequence from a single mitochondria

December 6, 2017, Perelman School of Medicine at the University of Pennsylvania
Manual isolation of a single live mitochondria. The mitochondria can be seen under a microscope where a thin glass tube can be used to isolate the mitochondria from the dendrite region of the mouse neuron. Credit: Jacqueline Morris and Jaehee Lee, Perelman School of Medicine, University of Pennsylvania

DNA sequences between mitochondria within a single cell are vastly different, found researchers in the Perelman School of Medicine at the University of Pennsylvania. This knowledge will help to better illuminate the underlying mechanisms of many disorders that start with accumulated mutations in individual mitochondria and provide clues about how patients might respond to specific therapies. The findings are published in Cell Reports this week.

Mitochondria, a component of that have their own DNA (mtDNA), produce energy for the body, among other functions. One mitochondrion can contain 10 or more different genomes with hundreds to thousands of individual mitochondria residing in each cell. A number of mitochondrial diseases arise from accumulating in mtDNA. For example, these mutations have been found in colorectal, ovarian, breast, bladder, kidney, lung, and pancreatic tumors.

Using methods developed in the lab of senior author James Eberwine, PhD, a professor of Systems Pharmacology and Translational Therapeutics, the investigators extracted single mitochondrion and then extracted its mtDNA. They compared mutations present in single mitochondrion in individual mouse and human neurons and found that had more accumulated mutations compared to human cells. Because of this finding that mutations accumulate at a different rate in mice versus humans, Eberwine notes that one important take away from the study is to ensure that or potential therapeutics in cells are examined in models where the mutations parallel those that occur in humans.

The process of mtDNA mutations accruing over a lifetime most likely happens somewhat differently in each person. The study addressed similarities and differences in discrete mtDNA in the same cell and also between cell types such as neurons and astrocytes in the brain. "By being able to look at a single mitochondrion and compare mutational dynamics between mitochondria, we will be able to gauge the risk for reaching a threshold for diseases associated with increasing numbers of ." For instance, these data may improve diagnosis for neurological diseases, potentially allowing physicians to detect cells that could become diseased or pinpointing patients who may develop certain conditions. This is particularly likely for conditions that more commonly strike the elderly in which mtDNA mutations have been found to accumulate with age.

In the future, the researchers plan to use this knowledge to find ways to slow the rate of mtDNA mutation accumulation in hopes of halting disease progression. "This roadmap of the location and number of mutations within the DNA of a mitochondrion and across all of a cell's mitochondria is where we need to start," Eberwine said.

Explore further: Higher number of mitochondrial DNA-molecules can compensate for negative effects of mutations

Related Stories

Higher number of mitochondrial DNA-molecules can compensate for negative effects of mutations

August 4, 2017
Male infertility can be caused by mutations in the DNA of mitochondria, the powerhouses of cells. By increasing the total DNA amount in mitochondria, scientists from the Max Planck Institute for Biology of Ageing in Cologne ...

Healthy people carry disease-causing mitochondrial DNA mutations

July 8, 2014
(Medical Xpress)—For the first time, researchers have discovered that disease-causing mutations in mitochondrial DNA (mtDNA) are common in healthy individuals, according to a Cornell study published July 7 in the Proceedings ...

Scientists discover novel mechanism that protects mitochondrial DNA

October 12, 2017
Researchers at the University of Eastern Finland have discovered a novel mechanism safeguarding mitochondrial DNA. The study, published in PNAS earlier this week, was carried out in close collaboration with research groups ...

Rare mitochondrial mutations—maybe not so rare?

June 8, 2013
French scientists have discovered that supposedly rare mutations in the mitochondria, the 'power plants' of human cells responsible for creating energy, account for more than 7% of patients with a mitochondrial disease manifesting ...

Recommended for you

Study of smoking and genetics illuminates complexities of blood pressure

February 15, 2018
Analyzing the genetics and smoking habits of more than half a million people has shed new light on the complexities of controlling blood pressure, according to a study led by researchers at Washington University School of ...

New mutation linked to ovarian cancer can be passed down through dad

February 15, 2018
A newly identified mutation, passed down through the X-chromosome, is linked to earlier onset of ovarian cancer in women and prostate cancer in father and sons. Kunle Odunsi, Kevin H. Eng and colleagues at Roswell Park Comprehensive ...

A gene that increases the risk of pancreatic cancer controls inflammation in normal tissue

February 14, 2018
Inflammation is a defensive response of the body to pathogens, but when it persists, it can be harmful, even leading to cancer. Hence, it is crucial to understand the relationship between inflammation and cancer. A group ...

Scientists develop low-cost way to build gene sequences

February 13, 2018
A new technique pioneered by UCLA researchers could enable scientists in any typical biochemistry laboratory to make their own gene sequences for only about $2 per gene. Researchers now generally buy gene sequences from commercial ...

New insights into gene underlying circadian rhythms

February 13, 2018
A genetic modification in a "clock gene" that influences circadian rhythm produced significant changes in the length and magnitude of cycles, providing insight into the complex system and giving scientists a new tool to further ...

Clues to aging found in stem cells' genomes

February 13, 2018
Little hints of immortality are lurking in fruit flies' stem cells.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.