Navigation Links
Alternate ending -- living on without telomerase
Date:11/3/2011

Scientists of the German Cancer Research Center have discovered an alternative mechanism for the extension of the telomere repeat sequence by DNA repair enzymes.

The ends of the chromosomes, the telomeres, are repetitive DNA sequences that shorten every time a cell divides during the process of duplicating its genome. Once the telomeres become very short the cell stops dividing. Thus, telomeres work like a cellular clock that keeps an eye on the number of cell divisions. And once the cell's time is over it can no longer divide. Circumventing this control mechanism is crucial for tumor cells in order to proliferate without limits. In the majority of tumors this is accomplished by reactivating telomerase, an enzyme that normally extends the telomeres only in embryonic cells, and thus resets the cellular clock during development. However, a 10-15% fraction of tumors keeps on dividing without telomerase by making use of what is called the ALT-mechanism for "Alternative Lengthening of Telomeres". The hallmark of ALT cancer cells is a special type of complexes of promyelocytic leukemia (PML) protein at the telomeres that are termed ALT-associated PML nuclear bodies or APBs.

ALT-tumors can be identified by the presence of APBs on fluorescence microscopy images since normal cells do not have these structures. However, the function of APBs has remained mysterious. In a recent study, Inn Chung and Karsten Rippe from the German Cancer Research Center together with Heinrich Leonhard from the LMU in Munich applied a novel approach to study APBs. They succeeded in artificially making APBs in living cells by tethering PML and other APB proteins to the telomeres. In this manner they could not only trace the assembly of APBs but were able to investigate what happens after APB formation. They could show that the de novo formed APBs induced the extension of the telomere repeat sequence by a DNA repair synthesis mechanism. This demonstrates for the first time that APBs have an important function for the alternative telomere lengthening mechanism, and suggests that disrupting APBs would stop proliferation of ALT-positive tumor cells once their telomeres become too short. This makes APBs a promising new target of cancer cells, in which the ALT mechanism is active.


'/>"/>

Contact: Dr. Sibylle Kohlstaedt
s.kohlstaedt@dkfz.de
Helmholtz Association of German Research Centres
Source:Eurekalert

Related biology news :

1. Multiple siblings from every gene: Alternate gene reading leads to alternate gene products
2. Grasses have potential as alternate ethanol crop, Illinois study finds
3. Possible alternate therapy for adults with poorly controlled asthma
4. Nostrils alternate to process competing odors
5. Mechanical stress can help or hinder wound healing depending on time of application
6. Extending the vase life of cut flowers: Pre-treatments and preservatives studied
7. Era of canopy crane ending; certain research and education activities remain
8. Neisseria meningitidis disseminates itself by sending out scouts
9. Vitamin E may increase or decrease the risk of pneumonia depending on smoking and exercise
10. In fending off diseases, plants and animals are much the same, research shows
11. Research proves gender-bending chemicals affect reproduction
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/4/2017)... Solutions, a global clinical research organization (CRO), announces the launch of ... 4, 2017. Shadow is designed to assist medical writers and biometrics ... the European Medicines Agency (EMA) in meeting the requirements for de-identifying ... ... ...
(Date:8/15/2017)... ivWatch LLC , a medical device company focused on improving the ... its ISO 13485 Certification, the global standard for medical device quality ... ... device for the early detection of IV infiltrations. ... "This is an important milestone for ivWatch, as it validates ...
(Date:6/30/2017)... , June 30, 2017 Today, ... developer and supplier of face and eye tracking ... Featured Product provider program. "Artificial ... innovative way to monitor a driver,s attentiveness levels ... from being able to detect fatigue and prevent ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... , ... October 12, 2017 , ... ... Wound Market with the addition of its newest module, US Hemostats & Sealants. ... for thrombin hemostats, absorbable hemostats, fibrin sealants, synthetic sealants and biologic sealants used ...
(Date:10/11/2017)... NJ (PRWEB) , ... October 11, 2017 , ... Personal eye wash is a basic ... one eye at a time. So which eye do you rinse first if a dangerous ... have Plum Duo Eye Wash with its unique dual eye piece. , “Whether ...
(Date:10/11/2017)... (PRWEB) , ... October 11, 2017 , ... Disappearing forests ... the lives of over 5.5 million people each year. Especially those living in larger ... startup Treepex - based in one of the most pollution-affected countries globally - decided ...
(Date:10/10/2017)... ... October 10, 2017 , ... For the second time ... US2020 STEM Mentoring Award. Representatives of the FirstHand program travelled to Washington, D.C. ... US2020. , US2020’s mission is to change the trajectory of STEM education in ...
Breaking Biology Technology: