Navigation Links
Detailed 3-D image catches a key regulator of neural stem cell differentiation in action

Researchers at the Salk Institute for Biological Studies in collaboration with scientists at the University of California, San Diego (UCSD) took a high resolution "action shot" of a protein switch that plays a crucial role in the development of the nervous system. Their findings, published in the Dec. 8 issue of the journal Molecular Cell, provide a template for the design of small molecule inhibitors to control that switch, a protein called Scp1, at will.

"Scp1 is an important brake that regulates the transition from neuronal precursor to mature neuron," explains senior author Joseph Noel, Ph.D, a Howard Hughes Medical Institute investigator at Salk. "Loosening the brake with an inhibitor would allow us to influence the timing of neuronal differentiation," he adds.

A finely tuned network of molecular "on" and "off" switches orchestrates the differentiation of embryonic stem cells into different tissue types. Being able to manipulate individual switches would allow scientists to nudge embryonic stem cells into becoming specific cell types, a plus for both basic research and potential therapies.

"At the moment, the differentiation of stem cells into neurons in a Petri dish is a little bit like a black box and not very efficient," explains co-author Samuel Pfaff, Ph.D., a professor in the Salk's Gene Expression Laboratory, who together with co-author Gordon Gill, Ph.D., of the Departments of Medicine and Cellular and Molecular Medicine at UCSD, found that Scp1 silences neuron-specific genes in non-neuronal cells last year. "Having a specific inhibitor would give us a lot of insight into the development of the fetal nervous system and would allow us to chemically push embryonic stem cells to acquire a neuronal fate in an informed way," adds Pfaff.

Scp1 belongs to group of proteins called small carboxyl-terminal phosphatases (SCPs) that are expressed in almost all tissues of the body. When active, Scp1 prevents the enzyme RNA polyme rase II from reading and switching on neuronal genes in tissues where they shouldn't be expressed, such as skin, muscle and liver. In the nervous system Scp1 is switched off, enabling RNA polymerase II to efficiently transcribe information encoded by neuronal genes and driving the maturation of neural stem cells into specialized neurons.

"Scp1 is an interesting twist on how genes can be regulated during development," says Pfaff. "In the past there has been a lot of emphasis on chromatin modifications and physical access to genes, but Scp1 regulates the activity of the enzyme that transcribes genes directly," he adds.

Scp1 is not the only protein that directly influences the activity of RNA polymerase II. A constantly fluctuating brigade of enzymatic foot soldiers regulates RNA polymerase II's activity by chemically modifying the long cord-like tail that hangs from its globular structure, like a chain on a light fixture.

Enzymes called kinases turn the "light" on by adding small phosphate chemical groups - giving RNA polymerase the go-ahead to transcribe genes - while removal of those phosphates by phosphatases like Scp1 turns out the light, effectively stopping RNA polymerase in its tracks.

Noel and postdoctoral fellow Yan Zhang, Ph.D, analyzed the crystal structure of Scp1 and RNA polymerase together and obtained a 3-dimensional image showing how Scp1 hangs onto the seven amino acid residues reiterated in the polymerase tail. "We captured Scp1 bound to a single seven amino-acid long repeat containing specific phosphates," explains Zhang, the paper's first author. "It turns out that only three amino acids are important for Scp1's ability to know how to remove phosphates from RNA polymerase."

She adds that knowing how enzymes like Scp1 precisely recognize that seven amino acid stretch is exactly the kind of "unambiguous information relevant for the design of a chemical inhibitor by a process known as structure-ba sed drug design."

Capitalizing on information gleaned from their structural studies, Noel's lab has already started that structure-based program. "We have designed the first generation of inhibitors and now it is a matter of chemically synthesizing them, testing them in test tubes and cells, and imaging them bound to Scp1 in 3D," says Noel. This will set the stage for the rational fine-tuning of their efficacy using an established process Noel likens to molecular dentistry, because his group is striving to shape inhibitory molecules to fit the groove in Scp1 much the same way that a dentist molds a filling to fit the cavity in a patient's tooth.
'"/>

Source:Salk Institute


Related biology news :

1. Key heart and Alzheimers disease protein imaged for first time in native state
2. New MRI technique quickly builds 3-D images of knees
3. Everything in its place: Researchers identify brain cells used to categorize images
4. With record resolution and sensitivity, tool images how life organizes in a cell membrane
5. Researchers image molecular motor structural changes
6. CSIRO imagery shows Outer Great Barrier Reef at risk from river plumes
7. Novel computed imaging technique uses blurry images to enhance view
8. Ultrasound upgrade produces images that work like 3-D movies
9. Researchers wake up viruses inside tumors to image and then destroy cancers
10. Novel system developed to turn data into real-time, interactive 3-D images
11. White blood cell waste disposal system plays critical regulatory role

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/22/2016)... -- On Monday, the Department of Homeland Security (DHS) ... for the Biometric Exit Program. The Request for Information ... explains that CBP intends to add biometrics to confirm ... States , in order to deter visa overstays, ... Logo - http://photos.prnewswire.com/prnh/20160622/382209LOGO ...
(Date:6/15/2016)... , June 15, 2016 ... market report titled "Gesture Recognition Market by Application Market - Global ... 2016 - 2024". According to the report, the  global ... billion in 2015 and is estimated to grow ... 48.56 billion by 2024.  Increasing application ...
(Date:6/3/2016)... 3, 2016 Das ... Nepal hat ein 44 ... geprägter Kennzeichen, einschließlich Personalisierung, Registrierung und IT-Infrastruktur, ... Produktion und Implementierung von Identitätsmanagementlösungen. Zahlreiche renommierte ... Januar teilgenommen, aber Decatur wurde als konformste ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... June 27, 2016  Global demand for enzymes ... through 2020 to $7.2 billion.  This market includes ... cleaning products, biofuel production, animal feed, and other ... and biocatalysts). Food and beverages will remain the ... increasing consumption of products containing enzymes in developing ...
(Date:6/27/2016)... ... June 27, 2016 , ... Parallel 6 , the leading ... the Clinical Reach Virtual Patient Encounter CONSULT module which enables both audio ... and clinical trial team. , Using the CONSULT module, patients and physicians can schedule ...
(Date:6/27/2016)...   Ginkgo Bioworks , a leading organism ... today awarded as one of the World Economic ... most innovative companies. Ginkgo Bioworks is engineering biology ... world in the nutrition, health and consumer goods ... customers including Fortune 500 companies to design microbes ...
(Date:6/24/2016)... ... ... Researchers at the Universita Politecnica delle Marche in Ancona combed medical journal ... Their findings are the subject of a new article on the Surviving Mesothelioma website. ... the blood, lung fluid or tissue of mesothelioma patients that can help point doctors ...
Breaking Biology Technology: