Freiburg, Tübingen, January 8, 2010. RNA molecules are the mobile messengers of genes. They carry information on the production of proteins from the DNA to the ribosomes. In addition to these messenger RNAs all living beings have micro RNAs that can hinder the messenger RNAs and thus the production of proteins. Biologists at the University of Freiburg, Germany, around Wolfgang Frank undRalf Reski from the Chair Plant Biotechnology have discovered that such micro RNAs also come into direct contact with genes, effectively turning off the genes in the process (CELL 140, January 8th, 2010).

With the exception of some viruses all living beings store their hereditary information, the sum of all their genes, as DNA. Active genes are transcribed into messenger RNAs (mRNAs) that function as blueprints for the production of proteins on ribosomes. Inactive genes are not transcribed into mRNAs. The fine balance between switched-on and switched-off genes differs between organs and changes during development and under varying environmental conditions. When this balance is disturbed disfiguration and illnesses such as cancer occur. In 2006 the American biologists Mello & Fire were awarded the Nobel Prize for their discovery that minute RNA molecules in the worm can attach themselves to mRNAs und thus hinder their translation into proteins.

The biologists in Freiburg together with researchers from the Max Planck Institute for Developmental Biology in Tuebingen have now, in the current issue of CELL, described how microRNAs not only indirectly turn off genes by obstructing mRNAs, but can also turn off genes directly. In the process the genes are silenced chemically by adding methyl groups. In the world of Biology such changes are termed as epigenetics.

The researchers at the Freiburg Chair Plant Biotechnology have found this novel mechanism for gene regulation in their favoured object of research, the moss.

When the biologists in Freiburg created so called knockout-mosses, they were surprised by the effect because it contradicted all existing expectations. Now they suspect that their newly discovered mechanism for gene regulation occurs not only in moss, but also in many other life forms, including us humans.

The work in Freiburg was supported by the Landesstiftung Baden-Wuerttemberg, the German Federal Ministry of Education and Research (BMBF) via the Freiburg Initiative for Systems Biology (FRISYS) as well the German Federal and State Excellence Initiative via the Centre for Biological Signalling Studies (bioss). One of the first authors of the publication, M. Asif Arif, was a scholarship holder from the German Academic Exchange Service (DAAD). The cover picture for the scientific study was supported by BioPro Baden-Wuerttemberg GmbH.

Original Publication:
"Transcriptional control of gene expression by microRNAs" (CELL 140, January 8th, 2010). Besides Dr. Frank and Prof. Reski, Dr. Basel Khraiwesh, M. Asif Arif, Dr. Gotelinde I. Seumel from Freiburg, and Stephan Ossowski and Prof. Detlef Weigel from the MPI Tuebingen were involved in this study. The idea for the cover picture came from Christoph Baechtle and Dr. Ralf Kindervater from BioPro Baden-Wuerttemberg, the artwork was carried out by Hannes Rall and Michael Meier.

Contact:
PD Dr. Wolfgang Frank
Prof. Dr. Ralf Reski
Chair Plant Biotechnology, University of Freiburg
Tel: +49 761 203-6968
Email: pbt[at]biologie.uni-freiburg.de
Homepage: www.plant-biotech.net

Prof. Dr. Detlef Weigel
Tel: +49 7071 601-1410 
Email: Detlef.Weigel[at]tuebingen.mpg.de
Dr. Susanne Diederich (Public Relations)
Tel: +49 7071 601 - 333
E-Mail: presse[at]tuebingen.mpg.de
Press release of the University of Freiburg.
http://www.pr.uni-freiburg.de/pm/2010/pm.2010-01-08.2/