Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A*STAR Scientists Discover Key Component in the Mother's Egg Critical for Survival of Newly Formed Embryo

30.03.2012
An international team led by scientists at A*STAR's Institute of Medical Biology (IMB) discovered that a protein called TRIM28, normally present in the mother's egg, is essential right after fertilisation[1] to preserve certain chemical modifications or 'epigenetic marks' on a specific set of genes. This newly published study paves the way for more research to explore the role that epigenetics might play in infertility.

Previous studies have shown that both nuclear reprogramming as well as 'imprinting' are vital for the survival and later development of the embryo. However, the underlying mechanisms governing the intricate interplay of these two processes during the early embryonic phase have not been clear, until now.

Nuclear Reprogramming

Immediately after fertilisation, the majority of the 'epigenetic marks' on the DNA from the sperm and egg cells are erased. The erasure process, termed nuclear reprogramming, allows the genes from the parents to be reset so that the early embryonic cells can develop into any cell types of the body.

Genomic Imprinting

On the other hand, certain 'epigenetic marks' on a particular set of genes, some from the mother and some from the father must be preserved. These genes are said to be 'imprinted' by their parent of origin and preservation of these marks is critical for the survival of the newly formed embryo. Expression of these imprinted genes at the appropriate levels ensures proper development of the embryo. If the 'epigenetic marks' on the 'imprinted' genes are not protected, severe and multiple developmental defects occur in the embryo.

Using genetically identical mice from an inbred mouse strain[2], Drs. Davor Solter and Barbara Knowles, Senior Principal Investigators at IMB, observed that none of the embryos resulting from the fertilisation of eggs lacking TRIM28 survived. The embryos died at varying stages of development, and had very different developmental defects. Given that most genetic diseases attributed to the lack of a single gene have consistently similar defects in every affected individual, the highly varied abnormalities observed in the maternal TRIM28-deficient, yet genetically identical mice, were peculiar.

To further elucidate these findings and the role of TRIM28 during nuclear reprogramming, Dr. Daniel Messerschmidt, the first author of this paper, collaborated with Dr. Anne Ferguson-Smith, a visiting Professor at A*STAR's Singapore Institute for Clinical Sciences (SICS), from the University of Cambridge, UK. Together, they conducted a comprehensive study on the epigenetic state and the level of expression of a group of imprinted genes known to be important for development. Using highly sophisticated microarray analysis and advanced biochemical techniques, they found that not only is the presence of TRIM28 protein important during this critical period, but the timing and amount of TRIM28 made available to the newly formed embryo greatly impacts the expression of these imprinted genes at later developmental stages.

Genomic imprinting was first described by Dr. Davor Solter at the Wistar Insitute and by Dr. Azim Surani at Cambridge University three decades ago.. Recently, Dr. Solter suggested that the interplay between nuclear reprogramming and genetic imprints could be explained by a simple analogy from school where the teacher writes a long string of formulas on the black board. At the end of the class, he marks stretches to be preserved for the next day's lecture (these are the imprinted marks) and asks the cleaning lady to erase the rest (she performs the reprogramming).

Dr. Solter said, "For the longest time, we didn't know why some bits of the formulas escaped erasure. Through this study, the mystery is finally revealed! We now know TRIM28 instructs the 'cleaning lady' which part of the formulas she should preserve."

Dr. Azim Surani, who was not involved in this study, said "This elegant study on TRIM28 provides significant mechanistic insights on how maternal factors in eggs ensure faithful epigenetic inheritance that plays a critical role during development. These findings are relevant not only for the widely practised in vitro fertilisation of eggs for the treatment of human infertility, but also more generally for highlighting the importance of epigenetic mechanisms in development and disease."

Dr. Knowles, the senior author of this paper said, "Lack of TRIM28 in their eggs could explain why some women consistently suffer from multiple failed pregnancies where embryos die at different time points, manifesting multiple, different abnormalities."

Prof. Birgitte Lane, Executive Director of IMB, said, "Understanding the role of differential epigenetic modifications is important for the study of human diseases and development. This study has unravelled a critical component essential for nuclear reprogramming. The mechanistic insights revealed have far-reaching clinical implications for treatment of diseases with patient-specific cell therapies. This finding demonstrates how discoveries of fundamental research can shed light on biological questions to open new avenues of formulating therapeutic strategies for the benefits of patients."

[1] Fertilisation in humans is the fusion of an egg with a sperm to produce an embryo, a new organism.

[2] Every mouse from an inbred strain is genetically identical (i.e. a twin) to every other mouse of the same strain. The inbred mouse strain used in this study originated from The Jackson Laboratory, where this study was initiated.

Notes for editors:
The research findings described in this news release can be found in the 23 Mar 2012 issue of Science under the title, "TRIM28 Is Required for Epigenetic Stability During Mouse Oocyte to Embryo Transition" by Daniel M. Messerschmidt (1), Wilhelmine de Vries (2), Mitsuteru Ito (3), Davor Solter (1,4), Anne Ferguson-Smith (3,5*), Barbara B. Knowles (1,6)
1. Mammalian Development Group, Institute of Medical Biology, 138648 Singapore.
2. The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA.
3. Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK.
4. Duke-NUS, Graduate Medical School,169857 Singapore.
5. Singapore Institute for Clinical Sciences, 117609 Singapore.
6. Department of Biochemistry, National University of Singapore, 117597 Singapore

* No longer at Singapore Institute for Clinical Sciences

Abstract of the article can be accessed from
http://www.sciencemag.org/content/335/6075/1499.abstract
About the Institute of Medical Biology (IMB)
IMB is one of the Biomedical Sciences Institutes of the Agency for Science, Technology and Research (A*STAR). It was formed in 2007, the 7th and youngest of the BMRC Research Institutes, with a mission to study mechanisms of human disease in order to discover new and effective therapeutic strategies for improved quality of life.

IMB hosts 20 research teams of international excellence in stem cells, genetic diseases, cancer and skin and epithelial biology, and works closely with clinical collaborators to target the challenging interface between basic science and clinical medicine. Its growing portfolio of strategic research topics is targeted at translational research on the mechanisms of human diseases, with a cell-to-tissue emphasis that can help identify new therapeutic strategies for disease amelioration, cure and eradication.

For more information about IMB, please visit www.imb..a-star.edu.sg.

About A*STAR

A*STAR, the Agency for Science, Technology and Research, is Singapore's lead agency for fostering world-class scientific research and talent for a vibrant knowledge-based Singapore. A*STAR actively nurtures public sector research and development in Biomedical Sciences, Physical Sciences and Engineering, with a particular focus on fields essential to Singapore's manufacturing industry and new growth industries. It oversees 19 research institutes and consortia and supports extramural research with the universities, hospital research centres and other local and international partners. At the heart of this knowledge intensive work is human capital. Top local and international scientific talent drive knowledge creation at A*STAR research institutes. The Agency also sends scholars for undergraduate, graduate and post-doctoral training in the best universities, a reflection of the high priority A*STAR places on nurturing the next generation of scientific talent. For more information, please visit www.a-star.edu.sg.

Contact:
Sarah Chang (Dr.)
Corporate Communications
Agency for Science, Technology and Research
Tel: +65-6826-6442
Email: chang_kai_chen@a-star.edu.sg

Sarah Chang (Dr.) | Research asia research news
Further information:
http://www..a-star.edu.sg
http://www.researchsea.com

More articles from Life Sciences:

nachricht Channels for the Supply of Energy
19.11.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Vine Compound Starves Cancer Cells
19.11.2018 | Julius-Maximilians-Universität Würzburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

How Humans and Machines Navigate Complex Situations

19.11.2018 | Science Education

Finding plastic litter from afar

19.11.2018 | Ecology, The Environment and Conservation

Channels for the Supply of Energy

19.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>