Navigation Links
Viable and fertile fruit flies in the absence of histone H3.3
Date:11/13/2012

Histones are proteins that are found in the cell's nucleus, where they are present in complexes with DNA and are presumed to play a regulatory role in all processes that take place on the DNA. These processes include transcription, namely RNA synthesis, and the duplication of DNA during cell division. Until now, the function of the individual histones in the various processes could only be determined indirectly. Molecular biologists Konrad Basler and Martina Hdl from the University of Zurich for the first time directly studied the function of two histones and one histone modification with surprising results: Viable and fertile organisms develop in the absence of the histone known as H3.3. Additionally a particular histone modification was believed to be crucial for the activation of gene transcription. However, the researchers were able to demonstrate that this is also not the case. The established models for the role and function of histones and their modifications during the transcription and cell-division need to be revised.

Fertile fruit flies despite lack of histone H3.3

For their study, Basler and his postdoctoral student Hdl used the fruit fly Drosophila melanogaster, the genome of which has been fully decoded. In an initial experiment, the scientists switched the two histone variants H3.2 and H3.3 in the cells. In normal (i.e. non-manipulated) cells, histone H3.2 is only expressed in one specific phase of the cell cycle, the so-called S phase. Histone H3.3, however, is always expressed. Consequently, it was assumed that histone H3.3 plays a key role in transcription, especially in reading genes. Thus, the general consensus was that RNA synthesis would be restricted in the absence of histone H3.3. "In our experiment, under lab conditions viable and fertile fruit flies could develop from cells that do not have any H3.3," explains Hdl, summing up the result that turns the previous understanding on its head. "Organisms also begin to develop from cells without H3.2 but these died in the first larval stage," Hdl continues.

Genes are switched on and off without histone modification

Histones are modified by different enzymes at different points in the protein. In a second experiment, Basler and Hdl examined the importance of modifications of the fourth amino acid of the protein, a lysine. Modification of this lysine is thought to play a key role in activating and deactivating the transcription of the gene. To test this, the scientists replaced the lysine with non-modifiable amino acids in all the histone H3 genes. The result was another big surprise. "Cells without this specific histone modification are able to divide normally," explains Basler before adding: "However, they do so considerably more slowly than cells that have not been modified." Therefore, the modification of this lysine is not essential for the activation of the genes.

The results show that the activation of genes and the inheritance of the ability to activate genes work differently than previously assumed. Clearly, the structure of the transcription process is extremely robust. According to Basler, the role of this common histone modification for cell function has been overestimated in recent years.


'/>"/>

Contact: Martina Hdl
martina.hoedl@imls.uzh.ch
41-446-353-115
University of Zurich
Source:Eurekalert  

Related biology news :

1. Could chloroplast breakthrough unlock key to controlling fruit ripening in crops?
2. Bees, fruits and money
3. Fruity science halves fat in chocolate
4. Study of fruit fly chromosomes improves understanding of evolution and fertility
5. Hormone in fruit flies sheds light on diabetes cure, weight-loss drug for humans
6. Virginia Tech and University of Tuscia lead team to unravel origin of devastating kiwifruit bacterium
7. Fruit flies provide new knowledge about uninhibited cell growth
8. First fruitful, then futile: Ammonites or the boon and bane of many offspring
9. An invasive Asian fly is taking over European fruit
10. Evolutionary straitjacket means flies cant take the heat
11. Massachusetts butterflies move north as climate warms
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Viable and fertile fruit flies in the absence of histone H3.3
(Date:4/24/2017)... Janice Kephart , former 9/11 ... Partners, LLP (IdSP) , today issues the following ... March 6, 2017 Executive Order: Protecting the ... be instilled with greater confidence, enabling the reactivation ... applications are suspended by until at least July ...
(Date:4/18/2017)... Calif. , April 18, 2017  Socionext Inc., a global ... of a media edge server, the M820, which features the company,s ... recognition software provided by Tera Probe, Inc., will be showcased during ... at the NAB show at the Las Vegas ... ...
(Date:4/13/2017)... 2017 UBM,s Advanced Design and Manufacturing event ... emerging and evolving technology through its 3D Printing and ... alongside the expo portion of the event and feature ... focused on trending topics within 3D printing and smart ... event will take place June 13-15, 2017 at the Jacob ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... Disappearing forests and increased ... of over 5.5 million people each year. Especially those living in larger cities are ... - based in one of the most pollution-affected countries globally - decided to take ...
(Date:10/10/2017)... ... October 10, 2017 , ... For the second time in ... STEM Mentoring Award. Representatives of the FirstHand program travelled to Washington, D.C. Tuesday, ... , US2020’s mission is to change the trajectory of STEM education in America ...
(Date:10/10/2017)... ... 10, 2017 , ... The Pittcon Program Committee is pleased ... scientists who have made outstanding contributions to analytical chemistry and applied spectroscopy. Each ... leading conference and exposition for laboratory science, which will be held February 26-March ...
(Date:10/9/2017)... ... October 09, 2017 , ... ... in the medical journal, Epilepsia, Brain Sentinel’s SPEAC® System which uses the ... in detecting generalized tonic-clonic seizures (GTCS) using surface electromyography (sEMG). The prospective ...
Breaking Biology Technology: