Featured Research

from universities, journals, and other organizations

Researchers Determine Composition Of Centromeric Chromatin

Date:
October 4, 2009
Source:
Stowers Institute for Medical Research
Summary:
Researchers have provided new evidence to clarify the structure of nucleosomes containing Cse4, a centromere-specific histone protein required for proper kinetochore function, which plays a critical role in the process of mitosis.

The Stowers Institute's Gerton Lab has provided new evidence to clarify the structure of nucleosomes containing Cse4, a centromere-specific histone protein required for proper kinetochore function, which plays a critical role in the process of mitosis. The work, conducted in yeast cells, was published in the most recent issue of Molecular Cell.

The centromeric nucleosome acts as a guide for the position of the kinetochore. The kinetochore attaches the chromosome to a microtubule for chromosome segregation. It is essential that chromosome segregation is carried out with high fidelity, since errors in this process can produce cells which contain an abnormal number of chromosomes. In humans, these types of errors are hallmarks of many types of cancer, and therefore are thought to play a significant role in tumor formation, malignancy, and metastasis.

For many years, researchers assumed that centromeric nucleosomes were structurally like other nucleosomes — "octamers" with two copies each of four different histone protein subunits with DNA wrapped around the outside. Recently, two alternative models for the structure of centromeric nucleosomes have been proposed. The first suggests that two of the histone protein pairs normally found in the centromere are replaced by the Scm3 protein, creating a hexameric nucleosome made up of six subunits. The second model suggested that centromeric nucleosomes contain a single molecule of each of the four proteins, forming a tetrameric structure called a hemisome.

The Gerton Lab provides evidence for a model in which Cse4-containing nucleosomes are, in fact, octamers. A variety of unbiased methods was used to test the three different models, including genetic, biochemical, and cell biological approaches. In the end, the octamer model was the only one consistent with all of the current experimental results.

"These data support a new model for the structure of centromeric nucleosomes and reinforce the importance of both structure and function of octameric nucleosomes in the epigenetic propagation of centromeric chromatin," said Raymond Camahort, Ph.D., formerly a Postdoctoral Research Associate and lead author on the paper. "In order to better understand how centromeric nucleosomes are formed, we must understand their composition. This work has answered a critical question of structure."

"Many lines of evidence indicate that centromeric chromatin is evolutionarily conserved from yeast to man," said Jennifer Gerton, Ph.D., Associate Investigator and senior author on the paper. "The octameric structure for centromeric nucleosomes may be universal. Our studies in budding yeast help to shed light on mechanisms of centromere propagation and chromosome transmission that are needed to maintain human health."

Additional contributing authors from the Stowers Institute include Manjunatha Shivaraju, Predoctoral Researcher; Mark Mattingly, Research Technician II; Bing Li, Ph.D., formerly a Senior Research Associate; Shima Nakanishi, Ph.D., Postdoctoral Research Fellow; Dongxiao Zhu, Ph.D., formerly a Biostatistician; Ali Shilatifard, Ph.D., Investigator; and Jerry Workman, Ph.D., Investigator.


Story Source:

The above story is based on materials provided by Stowers Institute for Medical Research. Note: Materials may be edited for content and length.


Journal Reference:

  1. Raymond Camahort, Manjunatha Shivaraju, Mark Mattingly, Bing Li, Shima Nakanishi, Dongxiao Zhu, Ali Shilatifard, Jerry L. Workman, Jennifer L. Gerton. Cse4 Is Part of an Octameric Nucleosome in Budding Yeast. Molecular Cell, 24 September 2009 (Vol. 35, Issue 6, pp. 794-805) DOI: 10.1016/j.molcel.2009.07.022

Cite This Page:

Stowers Institute for Medical Research. "Researchers Determine Composition Of Centromeric Chromatin." ScienceDaily. ScienceDaily, 4 October 2009. <www.sciencedaily.com/releases/2009/09/090928131024.htm>.
Stowers Institute for Medical Research. (2009, October 4). Researchers Determine Composition Of Centromeric Chromatin. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2009/09/090928131024.htm
Stowers Institute for Medical Research. "Researchers Determine Composition Of Centromeric Chromatin." ScienceDaily. www.sciencedaily.com/releases/2009/09/090928131024.htm (accessed July 30, 2014).

Share This




More Plants & Animals News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Raw: Otters Enjoy Water Slides at Japan Zoo

Raw: Otters Enjoy Water Slides at Japan Zoo

AP (July 30, 2014) River otters were hitting the water slides to beat the summer heatwave on Wednesday at Ichikawa City's Zoological and Botanical Garden. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins