Precision gene targeting in stem cells corrects disease-causing mutations
Using two distinct methods, Whitehead Institute researchers have successfully and consistently manipulated targeted genes in both human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells (adult cells that have been reprogrammed to an embryonic stem cell-like state).
In one case, scientists employed proteins known as zinc finger nucleases (ZFNs) to change a single base pair in the genome, allowing them either to insert or remove mutations known to cause early-onset Parkinson's disease (PD). The second method relies on proteins called transcription activator like effector nucleases (TALENs) capable of altering specific genes with similar efficiency and precision as ZFNs. Both sets of experiments were conducted in close collaboration with scientists at Sangamo BioSciences.
Targeted genetic manipulation addresses a problem that has been plaguing human stem cell research the ability to cleanly and site-specifically modify the genomes of human ES and iPS cells. Realizing the therapeutic promise of these cells depends on such changes to fix disease-causing mutations before the cells could be transplanted into patients or to create cell lines that researchers can use to study genetic diseases.
Such disease studiesthe much-heralded "disease in a dish" approachand the search for potentially disease-modifying drugs require the use of cells and controls that are genetically identical, except for a specific alteration whose impact can then be observed.
"This is very relevant for diseases like Parkinson's, which likely will display only subtle phenotypes in the Petri dish. It is very important that the cells be genetically identical and have the same history, then make or remove only that mutation," says Whitehead Founding Member Rudolf Jaenisch. "If you use control cells from one person and a diseased cell from another person, it's like comparing apples and oranges."
As reported in a paper published July 22 in Cell, first author Frank Soldner used ZFNs created by Sangamo BioSciences to generate, from both normal and PD patients' cells, sets of mutated and control cell lines. By either removing or adding a mutation to the alpha-synuclein gene associated with PD, Soldner created lines of cells whose genomes differ only by a single base pair. Subsequent differences seen in comparative studies of the cells can therefore be attributed to the mutation in question.
"ZFNs can transfer a mutation without any other alterations to the genome, such as leaving in unwanted pieces of DNA that could be harmful," says Soldner, a postdoctoral researcher in Jaenisch's lab. "This precision is ideal for drug research for PD and other diseases, but it is also one more step toward using ES or iPS cells therapeutically."
In its continual quest to refine human stem cell technology, the Jaenisch lab has also been investigating other gene targeting approaches. One option is to use TALENs, which use a type of DNA-binding domain originally found in some plant pathogens. TALENs can be designed and created in academic labs.
To compare TALENs' ability to alter genes to that of ZFNs', two postdoctoral researchers in Jaenisch's lab, Dirk Hockemeyer and Haoyi Wang, repeated an earlier ZFN experiment, this time using TALENs created by scientists at Sangamo BioSciences. In research reported earlier this month in Nature Biotechnology, Hockemeyer and Wang show that these TALENs can also modify genes as efficiently and precisely as ZFNs in ES and iPS cells.
"These are amazing proteins," says Wang. "In theory, everything ZFNs do, they should be able to do as well."
"This opens up a lot of possibilities of what we will be able do because the generation of TALENs is extremely versatile," adds Hockemeyer. "It appears they, along with ZFNs, will help us overcome the challenges of developing human ES and iPS cell technology."
More information: "Generation of isogenic pluripotent stem cells differing exclusively at two early onset Parkinson point mutations," Cell, July 22, 2011.
"Genetic engineering of human pluripotent cells using TALE nucleases," Nature Biotechnology, July 7, 2011.
Provided by Whitehead Institute for Biomedical Research
- Technique enables efficient gene splicing in human embryonic stem cells Aug 13, 2009 | not rated yet | 0
- Scientists create human embryonic stem cells with enhanced pluripotency May 03, 2010 | not rated yet | 0
- Human embryonic stem cells and reprogrammed cells virtually identical Aug 05, 2010 | not rated yet | 0
- Mature B cells reprogrammed to stem-cell-like state Apr 17, 2008 | not rated yet | 0
- What's good for the mouse is good for the monkey: Skin cells reprogrammed into stem cells Dec 03, 2008 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
Two mutations central to the development of infantile myofibromatosis (IM)—a disorder characterized by multiple tumors involving the skin, bone, and soft tissue—may provide new therapeutic targets, according to researchers ...
Genetics 4 hours ago | 5 / 5 (1) | 0 |
Can human genes be patented? That was the question posed by Alan J. Snyder, vice president and associate provost for research and graduate studies at Lehigh, and Lee Kaplan, scientific director of cellular and molecular genetics ...
Genetics 11 hours ago | 4 / 5 (1) | 0
Researchers from Queen Mary, University of London have led the largest sequencing study of human disease to date, investigating the genetic basis of six autoimmune diseases.
Genetics May 22, 2013 | 4.5 / 5 (4) | 0 |
University of Minnesota Medical School researchers from the Masonic Cancer Center, University of Minnesota, in partnership with the University's Brain Tumor Program, have developed a new mouse model of malignant peripheral ...
Genetics May 20, 2013 | 5 / 5 (1) | 0 |
Northwestern University scientists have shown a gene involved in neurodegenerative disease also plays a critical role in the proper function of the circadian clock.
Genetics May 16, 2013 | 3 / 5 (1) | 1 |
(Medical Xpress)—A new study by researchers in the US has shown that an ancient virus can be modified to help in the fight against the simian immunodeficiency virus SIV, which is the equivalent in monkeys ...
10 hours ago | 5 / 5 (3) | 0 |
Women at a particular stage in their monthly menstrual cycle may be more vulnerable to some of the psychological side-effects associated with stressful experiences, according to a study from UCL.
7 hours ago | 5 / 5 (1) | 0 |
Talking on a hands-free device while behind the wheel can lead to a sharp increase in errors that could imperil other drivers on the road, according to new research from the University of Alberta.
3 hours ago | not rated yet | 0
Biological processes are generally based on events at the molecular and cellular level. To understand what happens in the course of infections, diseases or normal bodily functions, scientists would need to ...
7 hours ago | 5 / 5 (2) | 0 |
Kate O'Reilly's spring allergy survival kit includes the usual stuff - nasal sprays, allergy pills and a box of tissues. This season, she's added a new weapon to her line of defense: an app on her smartphone.
5 hours ago | not rated yet | 0