Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How to make chromosomes from DNA

29.07.2015

Restoration of DNA structure shown to be prerequisite

Researchers at the University of Tokyo have discovered a long-overlooked process important for converting a long, string-like DNA molecule into a chromosome. This finding gives us a better understanding of the mechanism of how cells store safely genetic material, DNA.


*Model of condensin function revealed by the present study. © 2015 Takashi Sutani

DNA molecules are long, string-like polymers storing the genetic information of life and, in a cell, are tightly packed into structures called chromosomes. Formation of chromosomes in a dividing cell is required for faithful transmission of information in DNA to daughter cells. The condensin complex is known to play an essential role in assembling chromosomes, but it remains unknown how condensin is involved in folding of DNA molecules.

Researchers at the University of Tokyo, including Assistant Professor Takashi Sutani, Professor Katsuhiko Shirahige (Institute of Molecular and Cellular Biosciences) and Ph.D student Toyonori Sakata (Graduate School of Agricultural and Life Sciences), isolated from cells and analyzed DNA segments to which condensin binds, and revealed that condensin is associated with single-stranded DNA (ssDNA) which is produced by unwinding of the DNA double-helix.

By measuring the amount of ssDNA using an ssDNA binding protein, they found that ssDNA regions existed at expressed genes and were produced by gene expression (or transcription), and that ssDNA amount was further increased in condensin-deficient cells.

They also discovered that chromosome segregation defects in mutant cells that showed lowered levels of condensin function were largely rescued by transcription inhibition. They therefore concluded that ssDNA is produced by unwinding of double-stranded DNA during transcription, that ssDNA is detrimental to assembling chromosomes, and that condensin restores unwound ssDNA segments to double-stranded DNA.

“It was widely believed that unwound DNA segments return spontaneously to canonical double-helical DNA, but this study has revealed that restoration of double-stranded DNA is actively regulated and is important for cell survival. It has also demonstrated for the first time that the presence of ssDNA impedes chromosome organization, providing insight into the mechanism of chromosome formation,” says Assistant Professor Sutani.

This work was conducted in collaboration with the research group of Dr. Tatsuya Hirano (Chief Scientist at RIKEN Institute, Japan).

Image*
Condensin recognizes unwound DNA segments produced by gene expression and restores them to double-stranded DNA. This function proved to be a prerequisite for making chromosomes from DNA.

Paper
Takashi Sutani, Toyonori Sakata, Ryuichiro Nakato, Koji Masuda, Mai Ishibashi, Daisuke Yamashita, Yutaka Suzuki, Tatsuya Hirano, Masashige Bando & Katsuhiko Shirahige, "Condensin targets and reduces unwound DNA structure associated with transcription in mitotic chromosome condensation", Nature Communications Online Edition: 2015/7/23 (Japan time), doi: 10.1038/ncomms8815.


Associated links
UTokyo Research article

Euan McKay | ResearchSea
Further information:
http://www.researchsea.com

Further reports about: DNA DNA molecules DNA segments Hirano Takashi chromosomes double-stranded DNA

More articles from Life Sciences:

nachricht Warming ponds could accelerate climate change
21.02.2017 | University of Exeter

nachricht An alternative to opioids? Compound from marine snail is potent pain reliever
21.02.2017 | University of Utah

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>