Navigation Links
Study provides first look at the 'birth' of a retina cell

Scientists at the University of Michigan Kellogg Eye Center have gained new insight into the way an embryonic retina cell develops and then commits itself to a specific role. They have observed a small window of opportunity during which a cell has been designated to play a particular role, but has not yet begun to function as such.

The discovery provides a new vantage point for understanding how a healthy visual system develops. It also raises the possibility of re-directing the production of cell types as needed to stave off eye disease.

The study reports on the role of the gene regulator NRL, which was previously shown to be essential for the development of rods, the light-sensing cells required for vision.

Anand Swaroop, Ph.D., Harold F. Falls Collegiate Professor of Ophthalmology and Visual Sciences and Professor of Human Genetics, is senior author of both studies, the latest of which appears in the March 7 issue of the Proceedings of the National Academy of Sciences (PNAS).

In PNAS, Swaroop's team reports that NRL is the earliest marker of rod precursors, or cells that are fated to become rods. They achieved this unique and early view of rod development by creating a mouse model using an NRL regulatory DNA sequence to produce a protein that appears as fluorescent green when exposed to blue light. This fluorescent protein allows scientists to identify even a few cells that are destined to be rods at very early stages of development.

"For the first time we were able to see retina cells during early development, allowing us to pinpoint the exact time at which rods are 'born,'" says Swaroop. "Because the cells have been tagged, we can watch them at each step as they develop into mature and functional rods." Kellogg scientists then purified the rods at various stages and generated the profile of genes at each stage. This, for the first time, provided a handle for investigating the precise process of rod differentiation.

Rods, along with cones, are photoreceptors, which account for 70 percent to 80 percent of all cells in the adult retina. Rods greatly outnumber cones in the mouse and in humans.

Damage to photoreceptors is at the root of eye diseases such as diabetic retinopathy, retinitis pigmentosa, and macular degeneration. In most instances, including age-related macular degeneration, rod photoreceptors die before cones.

As the mouse eye develops, rods start out as stem cells, meaning they have not yet been assigned a function and could theoretically grow to become any kind of cell. Along the way, these cells change their gene expression and acquire competence to become a specific cell type. At a certain point, cell division stops, and the cell is fated to perform a certain function.

"We can now view rod precursor cells at a crucial juncture," says Swaroop. "They are committed to becoming rod cells, but they are still adaptable and have not yet 'become' that type of cell." In mouse models, it takes five to fourteen days for rod cells to become functional, whereas in humans this time period is four to five weeks during gestation.

The Swaroop research team also confirmed that when NRL is absent, a rod precursor will change its course and acquire the identity of a cone. "This finding in particular implies the existence of pools of progenitor cells with competence to become either a rod or a cone," explains Swaroop. "We suggest that during early stages of development, these cells are not completely committed to a specific fate; there is an opportunity for regulators such as NRL to instruct these cells to produce rods or cones."

With the ability to see greater detail in events along molecular pathways, Swaroop is enthusiastic about finding new methods for disrupting the disease process. There may also be opportunities to promote the production of new rods and cones when others die off.

In future studies, the Kellogg scientist pla ns to use this new mouse model in conjunction with other mouse models of specific diseases, such as macular and other retinal degenerations. Gene profiling of rods and cones in disease models at various stages of pathogenesis could help scientists identify molecular targets for drug treatment.

Swaroop is hopeful that his research group can use the fluorescent protein to illuminate the chain of events that occurs when a gene mutation interferes with rod -- or even cone -- development. "This model may give us the earliest look yet at some devastating diseases we are all eager to cure," he says.


'"/>

Source:University of Michigan Health System


Related biology news :

1. Novel Asthma Study Shows Multiple Genetic Input Required; Single-gene Solution Shot Down
2. Emory Study Tests Bone Marrow Stem Cells to Improve Circulation in Legs
3. UCLA Study Shows One-Third of Drug Ads in Medical Journals Do Not Contain References Supporting Medical Claims
4. Study Demonstrates Gene Expression Microarrays are Comparable and Reproducible
5. Study Links Ebola Outbreaks To Animal Carcasses
6. Breakthrough Microarray-based Technology for the Study of Cancer
7. NYU Study Reveals How Brains Immune System Fights Viral Encephalitis
8. Study finds more than one-third of human genome regulated by RNA
9. Leukemia Drug Breakthrough Study In New England Journal Of Medicine
10. Study identifies predictors of HIV drug resistance in patients beginning triple therapy
11. New Study from Affymetrix Laboratories Points to Changing View of How Genome Works
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/19/2016)... 2016 The new GEZE SecuLogic ... web-based "all-in-one" system solution for all door components. It ... the door interface with integration authorization management system, and ... The minimal dimensions of the access control and the ... installations offer considerable freedom of design with regard to ...
(Date:4/14/2016)... , April 14, 2016 ... Malware Detection, today announced the appointment of Eyal ... new role. Goldwerger,s leadership appointment comes at ... heels of the deployment of its platform at several ... biometric technology, which discerns unique cognitive and physiological factors, ...
(Date:3/31/2016)... R.I. , March 31, 2016  Genomics firm ... of founding CEO, Barrett Bready , M.D., who ... members of the original technical leadership team, including Chief ... President of Product Development, Steve Nurnberg and Vice President ... returned to the company. Dr. Bready served ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... Cancer experts ... they believe could be a new and helpful biomarker for malignant pleural mesothelioma. ... here to read it now. , Biomarkers are components in the blood, ...
(Date:6/27/2016)... Ginkgo Bioworks , a leading organism design company ... as one of the World Economic Forum,s Technology ... companies. Ginkgo Bioworks is engineering biology to manufacture ... the nutrition, health and consumer goods sectors. The ... Fortune 500 companies to design microbes for their ...
(Date:6/23/2016)... ... June 23, 2016 , ... Mosio, a leader ... “Clinical Trials Patient Recruitment and Retention Tips.” Partnering with experienced clinical research professionals, ... providing practical tips, tools, and strategies for clinical researchers. , “The landscape of ...
(Date:6/23/2016)... -- Houston Methodist Willowbrook Hospital has signed a ... serve as their official health care provider. As ... provide sponsorship support, athletic training services, and most ... athletes and families. "We are excited ... to bring Houston Methodist quality services and programs ...
Breaking Biology Technology: