Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Removing genes without a trace

30.09.2015

DNA repair mechanism manipulated to delete genes without leaving a scar

Genes may now be deleted without creating a scar in certain strains of Escherichia coli and other microorganisms, thanks to researchers at Agency for Science, Technology and Research (A*STAR) in Singapore [1]. The technique makes it easier to string together several genetic engineering steps without interference caused by a deletion scar.


A*STAR researchers have successfully deleted genes from Escherichia coli without leaving a scar.

© Eraxion/iStock/Thinkstock

Scientists currently delete genes by manipulating a process known as homologous recombination. Nucleotide sequences change places with the target gene during homologous recombination and are left behind as a genetic scar, undermining the effectiveness of subsequent deletions. As scars accumulate, the recombination process is more likely to recognize them than the target gene, disrupting the deletion attempt.

The scar-free deletion trick developed by Hua Zhao and colleagues at the A*STAR Institute of Chemical and Engineering Sciences utilizes a natural DNA repair mechanism. Gene duplication events or errors during replication occasionally lead to the formation of a mirrored DNA sequence known as an inverted repeat.

Since the repeated segments in an inverted repeat are complementary, they bind to each other and form a loop structure. While short loops have a biological role, longer loops can damage the genome and are therefore cut out by repair machinery.

“The key insight was the extreme instability of inverted repeats in the E. coli genome, which we and others observed. That prompted us to explore its application in gene deletion,” says Zhao.

To delete a gene, Zhao’s team prepares a DNA fragment, which includes an inverted repeat of part of the target gene. They then insert the fragment into the genome adjacent to the gene. The inverted repeats form a loop, and the repair machinery swoops in to snip them out. Since the repair process does not always happen, the team also engineers a selection marker into the fragment, enabling them to detect colonies in which it has been cut out.

Zhao’s team successfully repeated their method on three different E. coli genes. They also tested inverted repeats of different lengths to determine which worked best. While shorter repeats were less likely to be excised, longer repeats did not integrate into the genome as often.

Engineering E. coli to produce biochemicals often involves the deletion of multiple genes. According to Zhao, approaches presently only allow four genes to be deleted in sequence. “After that, further deletions create trouble because of recombination between the deletion scars. Our new method doesn’t introduce scars, so recombination won’t be a problem for multiple deletions.”

The A*STAR-affiliated researchers contributing to this research are from the Institute of Chemical and Engineering Sciences

Reference

[1] Tear, C. Y., Lim, C. & Zhao, H. Excision of unstable artificial gene-specific inverted repeats mediates scar-free gene deletions in Escherichia coli. Applied Biochemistry and Biotechnology 175, 1858–1867 (2015).


Associated links
Original article from A*STAR Research

A*STAR Research | Research SEA
Further information:
http://www.researchsea.com

Further reports about: A*STAR DNA fragment E coli Escherichia coli dna genes genetic engineering

More articles from Life Sciences:

nachricht BigH1 -- The key histone for male fertility
14.12.2017 | Institute for Research in Biomedicine (IRB Barcelona)

nachricht Guardians of the Gate
14.12.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Plasmonic biosensors enable development of new easy-to-use health tests

14.12.2017 | Health and Medicine

New type of smart windows use liquid to switch from clear to reflective

14.12.2017 | Physics and Astronomy

BigH1 -- The key histone for male fertility

14.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>