Navigation Links
Molecular steps involved in the creation of gene-silencing microRNAs identified

First discovered only a few brief years ago, microRNAs are small, remarkably powerful molecules that appear to play a pivotal role in gene silencing, one of the body's main strategies for regulating its genome. A scant 22 nucleotides in length, miRNAs appear to work by binding to and somehow interfering with messenger RNA, itself responsible for translating genes into proteins.

But how do miRNAs arise? And what can we learn about their biological function from their origins? In a study published last year in Nature, researchers at The Wistar Institute identified a two-protein complex, called the microprocessor complex, which controls the earliest steps in the creation of miRNAs in the cell nucleus.

Now, in a new study published online by Nature today, the Wistar group has identified a three-protein complex that picks up the process in the cell cytoplasm and carries it through to the maturation of the finished miRNAs.

Taken together, the two Nature studies trace the generation of miRNAs from the genes that give rise to long primary RNA molecules through to the mature miRNAs that target messenger RNA. Significantly, the research also shows that the finished miRNAs are associated with a protein called Argonaute 2, known to be involved in inactivating messenger RNA.

"In this study, we were able to link processing of the miRNAs directly through to the molecules responsible for silencing genes," says Ramin Shiekhattar, Ph.D., an associate professor at Wistar and senior author on both Nature studies. "The miRNAs provide specificity for those molecules, which do the actual work of gene silencing."

Intriguingly, the research also links the process of creating miRNAs with aspects of the HIV life cycle and with tumor suppression. The study identifies three proteins that work together in the cytoplasm to create finished miRNAs. Individually, each of the proteins was known previously, but their joint role in producing miRNAs is newly deline ated here. Equally as important, however, is the fact that while two of the proteins had been associated with miRNAs in earlier work, the third protein, TRBP, had not been. And TRBP is clearly a protein of interest to scientists.

"TRBP was first observed as a protein that binds to HIV during transcription of the virus," says Shiekhattar. "The tantalizing implication is that the RNA interference pathway may play a significant role in HIV replication. TRBP has also been identified as a tumor suppressor, which suggests still other connections to be explored."

The lead authors on the Nature study are Thimmaiah Chendrimada, Richard I. Gregory, and Easwari Kumaraswamy, with each contributing equally to the work. The remaining co-authors are Jessica Norman, Neil Cooch, and Wistar professor Kazuko Nishikura, Ph.D. Corresponding author Shiekhattar is an associate professor in two programs at Wistar, the gene expression and regulation program and molecular and cellular oncogenesis program. Support for the research was provided by the National Institutes of Health, the American Cancer Society, and the Jane Coffin Child Memorial Fund for Medical Research.


'"/>

Source:The Wistar Institute


Related biology news :

1. Molecular biology fills gaps in knowledge of bat evolution
2. Molecular machine may lead to new drugs to combat human diseases
3. Molecular Motors Cooperate In Moving Cellular Cargo, Study Shows
4. Molecular models advance the fight against malaria
5. Molecular fossils uncover link between viruses and the immune system
6. Molecular thermometers on skin cells detect heat and camphor
7. Molecular messengers perform a crucial role in the ability of injured nerve cells to heal themselves
8. Molecular miners find pain relief drugs from the sea
9. Molecular mechanism of feather formation found
10. Molecular trigger for Huntingtons disease found
11. Molecular Partners Required For Appropriate Neuronal Gene Repression
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:8/15/2017)... Va. , Aug. 15 2017   ivWatch LLC , ... of intravenous (IV) therapy, today announced receipt of its ISO 13485 ... developed by the International Organization for Standardization (ISO®). ... ivWatch Model 400 Continuous Monitoring device for the ... "This is ...
(Date:6/23/2017)... and ITHACA, N.Y. , June 23, ... University, a leader in dairy research, today announced a ... to help reduce the chances that the global milk ... of this dairy project, Cornell University has become the ... the Food Supply Chain, a food safety initiative that ...
(Date:5/16/2017)...  Veratad Technologies, LLC ( www.veratad.com ), an innovative ... verification solutions, announced today they will participate as a ... thru May 17, 2017, in Washington D.C.,s ... Identity impacts the lives of billions ... evolving digital world, defining identity is critical to nearly ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... , ... October 12, 2017 , ... ... Wound Market with the addition of its newest module, US Hemostats & Sealants. ... for thrombin hemostats, absorbable hemostats, fibrin sealants, synthetic sealants and biologic sealants used ...
(Date:10/11/2017)... ... October 11, 2017 , ... Personal eye wash is a basic first aid supply for ... time. So which eye do you rinse first if a dangerous substance enters both eyes? ... Eye Wash with its unique dual eye piece. , “Whether its dirt and debris, ...
(Date:10/11/2017)... Tbilisi, Georgia (PRWEB) , ... October 11, 2017 , ... ... disaster, taking the lives of over 5.5 million people each year. Especially those living ... the greenovative startup Treepex - based in one of the most pollution-affected countries globally ...
(Date:10/10/2017)... ... October 10, 2017 , ... For the second time ... US2020 STEM Mentoring Award. Representatives of the FirstHand program travelled to Washington, D.C. ... US2020. , US2020’s mission is to change the trajectory of STEM education in ...
Breaking Biology Technology: