Putting the squeeze on sperm DNA
CEA
super-suits. In the body, sperm are the only cells that swim and, as
speed is crucial to fertility, have developed their own ways to
become exceptionally streamlined. Scientists at the European
Molecular Biology Laboratory (EMBL) in Heidelberg and
Grenoble, the Institut de Biologie Structurale (IBS) and the
Institut Albert Bonniot, both also in Grenoble, have been studying
the secrets of speedy sperm. Their work, published today in
Nature, shows how a protein only found in developing sperm
cells, Brdt, directs tight re-packaging of sperm DNA.
Because it is such a long and unwieldy molecule, our DNA is packaged for convenience into a complex structure called chromatin: long DNA strands are wound around proteins called histones. In sperm, however, this package has become even more compact, reducing the size of the sperm head and making it more hydrodynamic. The nature of chromatin – how open or compact it is – is intricately regulated. Histones are marked with different chemical tags, often several per histone, that act as a code to direct changes in chromatin structure. Different proteins bind to the tags, the combination of which deciphers the code. Until now, scientists thought that these proteins bind using one or more modular ‘domains’, with each domain docking to just one tag. However, this new study reports the discovery of an extra level of sophistication. The researchers studied histone binding of a protein called Brdt, finding that it bindsmost strongly to a histone with Source Article Morinière, J., Rousseaux, S., Steuerwald, U., Soler-López, M., Curtet, S., Vitte, A-L., Govin, J., Gaucher, J., Sadoul, K., Hart, D.J., Krijgsveld, J., Khochbin, S., Müller, C.W. & Petosa, C. Cooperative binding of two acetylation marks on a histone tail by a single bromodomain. Contact: Lena Raditsch, Head of Communications, Heidelberg, Germany, Tel: +49 6221 387 125, www.embl.org, lena.raditsch@embl.de About EMBL The European Molecular Biology Laboratory is a basic research institute funded by public research monies from 20 member states ( conducted by approximately 80 independent groups covering the spectrum of molecular biology. The Laboratory has five units: the main Laboratory in Monterotondo near students and visitors at all levels; to offer vital services to scientists in the member states; to develop new instruments and methods in the life sciences and to actively engage in technology transfer activities. EMBL’s International PhD Programme has a student body of about 170. The Laboratory also sponsors an active Science and Society programme. Visitors from the press and public are welcome. About the IBS The Institut de Biologie Structurale Jean- Commission (CEA), the 12 independent groups (230 staff) performing interdisciplinary research at the interface of biology, physics and chemistry. In 2002 the IBS, EMBL and two other European institutes (the European Synchrotron Radiation Facility and the Institut Laue-Langevin) formed the Partnership for Structural Biology, whose primary objective is to study the structure and function of proteins and other biomolecules, particularly those involved in human disease. About the Albert Bonniot Institute The Albert Bonniot Institute is a research centre jointly operated by the French National Institute of Health and Medical Research (INSERM) and the University Joseph Fourier in staff). Research at the institute revolves around the understanding of basic mechanisms that govern cell and tissue differentiation and their pathological malfunctioning, especially in an oncogenic setting.