Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Bayreuth geneticists discover regulatory mechanism of chromosome inheritance


In the course of every single cell division, the genetic information on the chromosomes must be distributed equally between the newly developing daughter cells. The enzyme separase plays a decisive role in this process. Susanne Hellmuth and Olaf Stemmann from the Chair of genetics at the University of Bayreuth have now discovered a previously unknown mechanism that regulates the activity of the separase. These fundamental findings add a new aspect to our current understanding of chromosome inheritance. The scientists have presented their study in the journal "Nature".

Crucial for healthy cell development: the regulation of separase

Susanne Hellmuth M. Sc, PhD student at the Department of Genetics at the University of Bayreuth, here loading samples for the separation of proteins and their subsequent immunological detection.

Images: Olaf Stemmann

The separase cuts the cohesin rings, which hold the sister chromatids together. These then migrate to the opposite poles of the spindle apparatus.

Graphic: Olaf Stemmann

Cell division is essential for human growth and reproduction. Before a cell begins to divide, the genetic information stored on the chromosomes is duplicated. When this process is complete, each chromosome consists of two identical DNA threads, the sister chromatids.

Cohesin, a ring consisting of several proteins, encloses each chromosome and holds the pair of chromatids together. Already during preparation for cell division, cohesin is removed from the arms of the chromosomes. However, the complete separation of the sister chromatids can only take place when the cohesin remaining in the middle of the chromosomes is cut by the enzyme separase. The chromatids then migrate to the two opposite ends of the spindle apparatus, where they form the genetic basis of the forming daughter cells.

Healthy development of the daughter cells is only guaranteed if they do not contain genetic defects. In order for this condition to be fulfilled, the separase must become active at exactly the right time. If the sister chromatids are separated too early, they can only be distributed randomly. The resulting daughter cells then contain the wrong chromosome number and die, or they can develop into tumour cells. Only strict regulation of the separase prevents these genetic malfunctions.

A "guardian spirit" suppresses premature sister chromatid separation

The Bayreuth researchers Susanne Hellmuth and Olaf Stemmann, in cooperation with geneticists from the University of Salamanca/Spain, have now discovered that the protein shugoshin (Japanese for "guardian spirit") has exactly this regulating function. Shugoshin causes the separase to remain inactive until the right time for cohesin splitting has come.

With this discovery, scientists have succeeded in solving an important puzzle of genetics: Until now, only the protein securin was known to suppress premature activity of the separase. It was therefore believed that the separase was exclusively regulated by securin. However, this view contradicted the observation that separase remains properly regulated even when securin is not present.

The study now published in "Nature" provides the explanation: Shugoshin and securin both prevent separase from initiating the process of chromsosome segregation at the wrong time. And if the securin fails, even shugoshin alone is able to regulate the activity of separase in human cells.

"We are dealing with a type of redundancy that is not at all uncommon in the cell cycle: In order for a vital process to proceed in a well-ordered manner, nature has safeguarded it by controlling it simultaneously in two or more different ways. This makes the process particularly robust, but also difficult to study, because individual disturbances have no visible effect," said Susanne Hellmuth, first author of the study.

Dual control through the spindle checkpoint

Indeed, Hellmuth and Stemmann made a further discovery: It is the spindle assembly checkpoint (SAC) that controls the regulating influence of shugoshin as well as that of securin. This finding confirms the well-established assumption in the research that the SAC has, as it were, sovereignty over all processes involved in chromosome inheritance.

It had been known for some time that the SAC first stabilizes the securin and does not allow its degradation until the time has come for cohesin splitting by separase. The "Nature" publication now shows how the checkpoint causes shugoshin to suppress the premature activity of separase: namely by associating shugoshin with the SAC component Mad2.

"I was particularly pleased to hear a remark on our publication by one referee that the textbooks will now have to be rewritten," says Olaf Stemmann. "Our further research will show how our fundamental findings could also find their way into cancer therapy." This follow-up study by the Bayreuth research duo will also soon be published in "Nature".

Research funding:

The research work at the University of Bayreuth was funded by the German Research Foundation (DFG). Their research partners in Spain received funding from the Ministry for the Economy and Competitiveness (MINECO) and Junta de Castilla y León.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Olaf Stemmann
Chair of Genetics
University of Bayreuth
Phone: +49 (0)921 / 55-2701


Susanne Hellmuth, Laura Gómez-H, Alberto M. Pendás, Olaf Stemmann: Securin-independent regulation of separase by checkpoint-induced shugoshin-Mad2. Nature (2020), doi:

Christian Wißler | Universität Bayreuth
Further information:

More articles from Life Sciences:

nachricht Moss protein corrects genetic defects of other plants
02.07.2020 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht A new view of microscopic interactions
02.07.2020 | University of Missouri-Columbia

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

Im Focus: AI monitoring of laser welding processes - X-ray vision and eavesdropping ensure quality

With an X-ray experiment at the European Synchrotron ESRF in Grenoble (France), Empa researchers were able to demonstrate how well their real-time acoustic monitoring of laser weld seams works. With almost 90 percent reliability, they detected the formation of unwanted pores that impair the quality of weld seams. Thanks to a special evaluation method based on artificial intelligence (AI), the detection process is completed in just 70 milliseconds.

Laser welding is a process suitable for joining metals and thermoplastics. It has become particularly well established in highly automated production, for...

Im Focus: A structural light switch for magnetism

A research team from the Max Planck Institute for the Structure of Dynamics (MPSD) and the University of Oxford has managed to drive a prototypical antiferromagnet into a new magnetic state using terahertz frequency light. Their groundbreaking method produced an effect orders of magnitude larger than previously achieved, and on ultrafast time scales. The team’s work has just been published in Nature Physics.

Magnetic materials have been a mainstay in computing technology due to their ability to permanently store information in their magnetic state. Current...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

Latest News

The lightest electromagnetic shielding material in the world

02.07.2020 | Materials Sciences

Spintronics: Faster data processing through ultrashort electric pulses

02.07.2020 | Information Technology

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Science & Research
Overview of more VideoLinks >>>