Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Good housekeeping

18.02.2008
A protein with an important role in regulating gene expression may have other duties relating to chromosome maintenance

Most genetic information is directly encoded by the sequence of nucleotides in a chain of DNA, but further instructions may also be provided by adding chemical modifications to those nucleotides, just like inserting footnotes can alter the meaning of a text. One important modification is DNA methylation, which generally has the effect of ‘silencing’ transcriptional activity of marked genes—a secondary but essential level of regulation.

DNA methylation patterns can be transmitted from parent to child, an important process known as genomic ‘imprinting.’ Maintaining these patterns is an active process, as each cycle of DNA replication results in the production of chains that are only hemimethylated, and full methylation is subsequently restored by the enzyme DNA methyltransferase 1 (Dnmt1).

Other proteins are known to assist this process. Recent work from a group led by Haruhiko Koseki of the RIKEN Research Center for Allergy and Immunology in Yokohama, and Masaki Okano of the RIKEN Center for Developmental Biology in Kobe, has highlighted the important role of one particular protein, Np95, in directing Dnmt1 to hemimethylated DNA targets (1).

... more about:
»DNA »Dnmt1 »Np95 »methylation »modification

Koseki’s group initially found that Np95 associates with imprinting-related proteins, and subsequent experiments in mouse embryonic stem cells (ESCs) extended these findings, demonstrating that Np95 co-localizes with Dnmt1 and other associated proteins at hemimethylated chromosomal regions after DNA replication (Fig. 1). Eliminating the expression of Np95 altogether resulted in a marked reduction of DNA methylation in cultured ESCs, and led to full developmental arrest in mouse embryos.

Methylation does more than silence genes; it also helps stabilize DNA elements known as retrotransposons, which are otherwise capable of physically ‘jumping’ into other chromosomal regions—and potentially disrupting other genes. Koseki’s group found that Np95 helps to lock down these retrotransposons. “At the least, Np95 is essential to maintain genomic imprinting, which in turn permits normal development of embryonic and extraembryonic tissues,” he says. “But it could be possible that this process may also be important to ensure genomic stability.”

Intriguingly, Koseki’s and his colleagues also found evidence suggesting that Np95’s function may not be limited to restoring DNA methylation, but could encompass other chromosomal maintenance tasks as well—a possibility he is keen to investigate further. “Hemimethylated DNA is not simply a transient status that appears after DNA replication … it may potentially form a specific signal that could be sensed by Np95,” he says. “We presume that Np95 may form a platform that helps to organize not only DNA methylation but also other types of modifications.”

Reference

1. Sharif, J., Muto, M., Takebayashi, S., Suetake, I., Iwamatsu, A., Endo, T.A., Shinga, J., Mizutani-Koseki, Y., Toyoda, T., Okamura, K. et al. The SRA protein Np95 mediates epigenetic inheritance by recruiting Dnmt1 to methylated DNA. Nature 450, 908–912 (2007).

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/388/

Further reports about: DNA Dnmt1 Np95 methylation modification

More articles from Life Sciences:

nachricht First use of vasoprotective antibody in cardiogenic shock
17.05.2019 | Deutsches Zentrum für Herz-Kreislauf-Forschung e.V.

nachricht A nerve cell serves as a “single” for studies
15.05.2019 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

Im Focus: A step towards probabilistic computing

Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future

When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...

Im Focus: Recording embryonic development

Scientists develop a molecular recording tool that enables in vivo lineage tracing of embryonic cells

The beginning of new life starts with a fascinating process: A single cell gives rise to progenitor cells that eventually differentiate into the three germ...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Discovering unusual structures from exception using big data and machine learning techniques

17.05.2019 | Materials Sciences

ALMA discovers aluminum around young star

17.05.2019 | Physics and Astronomy

A new iron-based superconductor stabilized by inter-block charger transfer

17.05.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>