Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Opening and closing the genome

26.02.2007
Newly identified enzyme orchestrates access to genes for transcription

At any given time, most of the roughly 30,000 genes that constitute the human genome are inactive, or repressed, closed to the cellular machinery that transcribes genes into the proteins of the body. In an average cell, only about one in ten genes is active, or expressed, at any given moment, with its DNA open to the cell' transcriptional machinery.

A dynamic cast of gatekeeper enzymes controls this access to the DNA, adding and removing particular molecules to open or close the genome to transcription as needed. Fully explicating the complex interplay among these enzymes and the molecules they manage has been a primary goal for scientists seeking to understand the mechanisms governing gene control. These mechanisms are vital for health-- when they go wrong, diseases like cancer can result.

In study published online February 22 in Cell, researchers at The Wistar Institute identify an important new player in this gene-control system, an enzyme responsible for removing certain molecules, or marks, involved in opening or closing chromatin, the material that makes up chromosomes. The activity of this enzyme is thought to be widespread in the genome, likely affecting many genes.

... more about:
»Chromatin »Histone »Shiekhattar

"This enzyme removes methyl groups from a specific location where they facilitate opening of the chromatin for gene expression, and therefore this enzyme maintains a repressed state of gene expression," says Ramin Shiekhattar, Ph.D., a professor at The Wistar Institute and senior author on the Cell study. Currently, Shiekhattar is also a professor at the Center de Regulacio Genomica in Barcelona. "When the enzyme is not present, however, the marks are not removed, and the chromatin remains open for transcription."

The enzyme, called JARID1d, is the first identified member of a new family of enzymes that removes trimethylation from histone H3 at the lysine 4 location. Histones are critical components of chromatin. In mammalian genomes, trimethyl groups at the lysine 4 location of this histone have been known to be associated with gene activation. Shiekhattar and his team hypothesized the existence of an enzyme that would remove these trimethyl groups.

"We and others had wondered whether there might not be an enzyme able to remove these trimethyl marks," says Shiekhattar. "Such an enzyme would have the effect of setting the genes back to their original repressed state."

An important aspect of the work by Shiekhattar and his colleagues is their demonstration of an intimate connection between the histone demethylase enzyme JARID1d and Ring6a, a polycomb-like protein. Polycomb proteins are also known to play an important role in gene repression. Indeed, the findings show that Ring6a has the ability to regulate the enzymatic activity of the histone demethylase in vitro as well as in vivo. These results extend the role of transcriptional inhibitory polycomb complexes through their physical and functional link with histone demethylase enzymes.

Franklin Hoke | EurekAlert!
Further information:
http://www.wistar.org

Further reports about: Chromatin Histone Shiekhattar

More articles from Life Sciences:

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

nachricht First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>