Tags on, tags off: Scientists identify new regulatory protein complex with unexpected behavior

May 3, 2010
These microscopy images show the region of the embryo larva that will develop into the adult fruit fly's wing. In cells genetically manipulated so that PR-DUB cannot remove the gene-silencing tag (left), a gene which would normally be silenced becomes turned on (red) -- a situation which is corrected when PR-DUB's activity is restored (right). Credit: J. Mueller/EMBL

During embryonic development, proteins called Polycomb group complexes turn genes off when and where their activity must not be present, preventing specialised tissues and organs from forming in the wrong places. They also play an important role in processes like stem cell differentiation and cancer. In a study published online today in Nature, scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, identified a new Polycomb group complex, and were surprised by how it acts.

Another Polycomb group complex was already known to silence by placing a chemical tag near them. Juerg Mueller and his group at EMBL found that the new Polycomb complex they discovered, PR-DUB, removes that same tag.

"Surprisingly, this new complex which takes the tag off seems to act in the same tissues and at the same developmental stages as the one that puts the tag on," says Mueller, "and both opposing activities must occur to keep the gene silenced in our , the fruit fly Drosophila."

The reason for this unexpected behaviour is yet to be experimentally confirmed, but it may be a case of fine-tuning, with the newly-found complex ensuring that the chemical tagging is kept at its optimal level.

The human equivalent of PR-DUB is known to be a tumour-suppressor, and Mueller and colleagues discovered that, in test-tubes at least, it behaves the same way as the fruit fly complex, removing that same gene-silencing tag. Knowing how the complex acts in the fruit fly could help scientists uncover its function in the cells of mammals such as ourselves, and thus begin to shed light on its relation to cancer.

Explore further: Sugarcoating fruit fly development

Related Stories

Sugarcoating fruit fly development

May 29, 2009

Proteins are the executive agents that carry out all processes in a cell. Their activity is controlled and modified with the help of small chemical tags that can be dynamically added to and removed from the protein. 25 years ...

Cancer is a stem cell issue

February 19, 2007

There is an urgent reason to study stem cells: stem cells are at the heart of some, if not all, cancers. Mounting evidence implicates a clutch of rogue stem cells brandishing ‘epigenetic’ marks as the main culprits in ...

Opening and closing the genome

February 22, 2007

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 ...

Recommended for you

New analysis of big data sheds light on cell functions

October 26, 2016

Researchers have developed a new way of obtaining useful information from big data in biology to better understand—and predict—what goes on inside a cell. Using genome-scale models, researchers were able to integrate ...

Researchers identify genes for 'Help me!' aromas from corn

October 25, 2016

When corn seedlings are nibbled by caterpillars, they defend themselves by releasing scent compounds that attract parasitic wasps whose larvae consume the caterpillar—but not all corn varieties are equally effective at ...

Structure of key DNA replication protein solved

October 25, 2016

A research team led by scientists at the Icahn School of Medicine at Mount Sinai (ISMMS) has solved the three-dimensional structure of a key protein that helps damaged cellular DNA repair itself. Investigators say that knowing ...

Genome editing: Efficient CRISPR experiments in mouse cells

October 25, 2016

In order to use the CRISPR-Cas9 system to cut genes, researchers must design an RNA sequence that matches the DNA of the target gene. Most genes have hundreds of such sequences, with varying activity and uniqueness in the ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.