Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A nucleotide change could initiate fragile X syndrome

01.09.2014

Researchers reveal how the alteration of a single nucleotide—the basic building block of DNA—could initiate fragile X syndrome, the most common inherited form of intellectual disability. The study appears in The Journal of Cell Biology.

Fragile X syndrome is caused by a defect in a gene on the X chromosome called fragile X mental retardation 1 (FMR1). Around 1 in 230 women and 1 in 360 men carry a so-called premutation, in which a series of DNA repeats at one end of the FMR1 gene is slightly longer than normal.


Researchers used genetic mapping to determine that stem cells derived from mothers carrying a fragile X premutation (above) show a normal pattern of DNA replication when a nearby DNA sequence is similar to normal stem cells.

Credit: Gerhardt et al., 2014

These repeats are prone to even further expansion when FMR1 is passed from mother to child, causing the gene to switch off and stop producing a protein that is important for some cognitive functions.

A group of researchers from Albert Einstein College of Medicine of Yeshiva University in New York previously found that a certain site that initiates DNA replication, located near to the FMR1 gene, is inactivated in fragile X embryonic stem cells.

... more about:
»Biology »DNA »FMR1 »Fragile »Health »JCB »Rockefeller »SNP »cytosine »replication »thymine

This inactivation changes the way that the FMR1 gene is copied during cell division, which could pose problems that lead to expansion of the DNA repeats within the gene.

Intriguingly, a specific alteration in the DNA sequence near the FMR1 gene—a "single-nucleotide polymorphism" or SNP— has been linked to an increased risk of repeat expansion in some premutation carriers. These researchers discovered that this SNP overlaps with the inactive replication origin in fragile X embryonic stem cells.

Nucleotides in DNA include one of four bases (cytosine, thymine, adenine, or guanine). The researchers found that normal embryonic stem cells had a thymine base at the SNP site and an active replication origin. Fragile X cells, in contrast, had a cytosine base and an inactive origin.

The researchers also derived embryonic stem cells from mothers carrying the fragile X premutation. These cells had a thymine base and a normal replication pattern and, accordingly, showed no tendency to expand their repeat numbers over time.

The findings show that the substitution of cytosine for thymine might inactivate the DNA replication origin when the FMR1 gene is passed from mother to child, increasing the risk of DNA repeat expansions that can lead to fragile X syndrome.

###

Gerhardt, J., et al. 2014. J. Cell Biol. doi:10.1083/jcb.201404157

About The Journal of Cell Biology

The Journal of Cell Biology (JCB) is published by The Rockefeller University Press. All editorial decisions on manuscripts submitted are made by active scientists in conjunction with our in-house scientific editors. JCB content is posted to PubMed Central, where it is available to the public for free six months after publication. Authors retain copyright of their published works, and third parties may reuse the content for non-commercial purposes under a creative commons license. For more information, please visit http://www.jcb.org.

Research reported in this press release was supported by the National Institute of General Medical Sciences and National Institute of Child Health and Human Development of the National Institutes of Health, Empire State Stem Cell Fund, Starr Tri-Institutional Stem Cell Initiative, and Neurogenomics.

Rita Sullivan King | Eurek Alert!

Further reports about: Biology DNA FMR1 Fragile Health JCB Rockefeller SNP cytosine replication thymine

More articles from Life Sciences:

nachricht Stick insects produce bacterial enzymes themselves
31.05.2016 | Max-Planck-Institut für chemische Ökologie

nachricht New Model of T Cell Activation
27.05.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Worldwide Success of Tyrolean Wastewater Treatment Technology

A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.

The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...

Im Focus: Computational high-throughput screening finds hard magnets containing less rare earth elements

Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.

The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...

Im Focus: Atomic precision: technologies for the next-but-one generation of microchips

In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.

In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...

Im Focus: Researchers demonstrate size quantization of Dirac fermions in graphene

Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices

Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.

Im Focus: Graphene: A quantum of current

When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene

In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

International expert meeting “Health Business Connect” in France

19.05.2016 | Event News

 
Latest News

Stick insects produce bacterial enzymes themselves

31.05.2016 | Life Sciences

In a New Method for Searching Image Databases, a Hand-drawn Sketch Is all it Takes

31.05.2016 | Information Technology

Consensus in the Fight Against Colorectal Cancer

31.05.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>