Navigation Links
Alternative Splicing - Molecular Cloning

Alternative splicing is a molecular processwhich enables multiple genes to be produced from a single gene. By regulating this process, //cells can produce a wide variety of proteins from a finite number of genes. A new RNA map, created by researchers at Rockefeller University and the Howard Hughes Medical Institute, shows how the specific location of short snippets of RNA affects the way that alternative splicing is controlled in the brain.

Though scientists have begun to appreciate how alternative splicing adds a layer of complexity to brain processes that enable us to think and learn, exactly how alternative splicing is regulated during these processes — and in some cases is uncontrolled (or dysregulated) to cause disease — has remained elusive. The map provides the first comprehensive understanding of how alternative splicing works throughout the genome. The results have implications for a better understanding of such brain functions as learning and memory, neurological diseases and cancer biology.

'This finding is a significant advance in our understanding of splicing, and it suggests that it will be possible to understand how different splicing factors weave together to regulate complex patterns of genes, which in turn is relevant to generating complexity of function,' says senior author Robert Darnell, professor and head of the Laboratory of Molecular Neuro-oncology at Rockefeller and investigator at HHMI.

To understand what alternative splicing is, we first need to know what RNA splicing is. RNA splicing is the process by which the initial RNA copy of a gene, known as pre-mRNA, is pieced together to produce a mature mRNA that codes for cellular proteins. In alternative splicing, different piecesof this pre-mRNA, called exons, are stitched together to produce different mRNAs, and thus different proteins. The exon can be spliced in or out in a binary, computer-like fashion.Carefully regulated, such cellscan now produce a wide variety of proteins from a finite number of genes. This capacity is believed to be critical to the complex workings of human cells such as those found in the neurons of the brain.

The researchers focused on a brain protein called Nova, that binds to RNA. Nova was first identified by Darnell and his colleagues in 1993, as the target protein in a neurodegenerative disease termed POMA (paraneoplastic opsoclonus-myoclonus ataxia). POMAis also associated with several types of cancers. Since then the laboratory has focused on identifying RNA sequences — and in particular, identifying alternatively spliced pre-mRNAs — that Nova binds to. In the last three years, in work published in Science and Nature Genetics, the Darnell lab identified over 50 Nova-regulated alternatively spliced exons, using new techniques developed at Rockefeller.These techniques were specifically designed to find Nova RNA targets and the results were validated in knockout mice that were missing Nova.

In the new study, Darnell, with co-first authors Jernej Ule and Giovanni Stefani, took these 50 RNA transcripts and searched them for clusters of sequences they had previously identified as Nova binding sites through biochemical andx-ray crystallographic studies. The latter was in collaboration with Stephen Burley,a structural biologist of Rockfeller University. Unexpectedly, this search revealed four discrete peaks where the binding clusters locate. Furthermore, the location of the peaks correlated with Nova’s action on regulating whether the alternative exon is spliced in or out.

The researchers tested whether this RNA map was valid by asking whether it could predict how Nova would act on RNA transcripts that had yet to be discovered. They took a bioinformatics approach, using a database of all alternatively spliced RNAs compiled by co-authors Terry Gaasterland and Bahar Taneri, to search for new genes that had clusters of Nova binding sites. Of the 50 or so transcripts with such clusters, 30 turned out to be alternatively spliced in a Nova-dependent way. Of those, all 30 fit the rules of the RNA map.

'In other words, every transcript that we could predict as a Nova-regulated alternatively spliced RNA fit the prediction of this map,' says Darnell. 'Half of them were inhibited by Nova and half were enhanced in their exon use by Nova, and every one very cleanly fit the pattern.'

The researchers also simulated alternative splicing in the test tube, mixing purified RNA and a splicing extract. When purified Nova was added to the extracts, it bound to the mRNA clusters, altering the outcome of how the splicing machinery was able to assemble in a manner that again conformed to the predictions of the RNA map. In one case, Nova blocked specific components of the splicing machinery; in another it enhanced the ability of this machinery to assemble the right way and use an alternatively spliced site that is otherwise poorly utilized.

By offering a global understanding of how alternative splicing works across the genome, the map has implications for the treatment of a growing list of human neurologic diseases in which RNA regulation, and particularly RNA splicing, has been implicated as the primary cause. This also includes certain types of cancer and a number of brain and muscle disorders.

'Given that the complexity of the brain is orders and orders of magnitude more complex than the number of genes we have, one of the intriguing things about alternative splicing is that a relatively small number of regulatory splicing factors acting in concert on a single transcript can potentially generate a large number of different protein variants,' says Darnell.

'There is a converging set of observations indicating that as neurologic diseases are better understood, alternative splicing is going to play an important role in generation of disease and therefore an important role in n ormal generation of cognitive function,' he adds. 'Our new work lays out an approach to developing a global understanding of how alternative splicing is regulated by one disease-associated protein, Nova, offering a route by which scientists may now be able to approach a number of diseases with a fresh start.'

Finally, Darnell's work has shown that Nova is expressed in certain types of cancer cells. Cancer cells operate by dysregulating gene expression, and Darnell believes that further studies are needed to determine whether Nova is a cause of dysregulated gene expression at the level of alternative splicing in a cancer cell.

'The right splicing factor in the wrong environment could wreak havoc and change the quality of proteins in a tumor cell,' he says.

Source-Eurekalert/A
'"/>




Related medicine news :

1. Prince Charles lends support to Alternative Medicine
2. Alternative medicine more popular among HIV positive patients
3. Complementary and Alternative medicine
4. Alternative therapies popular with Parkinsons patients
5. Alternative to blood Transfusions
6. Alternative Therapy in HIV Patients
7. An Alternative to Warfarin
8. Another Alternative For Diabetics On Insulin
9. The Use Of Alternative Medicine On The Rise
10. Heart Patients Use Alternative Medicine
11. New Blood Thinner Pill - First Potential Alternative to Warfarin in 50 years
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/22/2017)... ... March 23, 2017 , ... Catalent Pharma Solutions, ... biologics and consumer health products, today announced that it had won the ‘Clinical ... at the Suntec Singapore International Exhibition & Convention Centre, Singapore. The award was ...
(Date:3/22/2017)... ... 2017 , ... Old School Labs™, makers of the best-selling Vintage line of ... Ambassador. Theophane, who trained with Floyd Mayweather, made his professional debut in London in ... an impressive number of wins in contests in Britain, Germany and the U.S. ...
(Date:3/22/2017)... ... 22, 2017 , ... Wash Tower Ltd. has released a series of six ... the world's first standalone constant pressure bidet. , The videos in the series titled ... https://www.washtower.com as well as on its social media pages. , Each video stars ...
(Date:3/22/2017)... (PRWEB) , ... March 22, 2017 , ... Drs. Jennifer ... their patient base to accept new patients in need of skilled pediatric dentistry ... India Hook Dental Care offers pediatric patients routine treatments, including cavities, sealants and fluoride ...
(Date:3/22/2017)... ... March 22, 2017 , ... ... lab with extensive therapeutic experience and operational excellence in oncology clinical trials, proudly ... trial for the treatment of non-small cell lung cancer and small cell lung ...
Breaking Medicine News(10 mins):
(Date:3/22/2017)... 22, 2017 FinancialBuzz.com News Commentary ... rapidly due to the significant development and innovation in ... Market Research, the global electrophysiology market was worth $3.42 ... billion by 2022, with a GAGR of 13.4%. Electrophysiology ... diagnose abnormal heartbeats or arrhythmia. The report indicates that ...
(Date:3/22/2017)... GROVE, Minn. , March 22, 2017   Upsher-Smith ... Clomipramine Hydrochloride Capsules* USP, 25 mg, 50 mg and 75 ... (clomipramine hydrochloride) Capsules USP. The clomipramine hydrochloride ... the 12 months ending December 2016, according to IMS Health. ... "Upsher-Smith ...
(Date:3/22/2017)... 22, 2017  As the world,s leading non-profit dedicated ... (LLS) has played a role in most therapies used ... are even helping patients with other cancers and serious ... investment in cutting-edge research – more than $1 billion ... with the record-breaking sum of $4.1 million raised at ...
Breaking Medicine Technology: