Rules of resistance against transgene silencing

January 28, 2021

Clear rules for engineering transgenes that can be inserted and propagated over multiple generations of nematodes include ways to protect inserted genes from the organism's natural defenses against foreign DNA. Developed by KAUST researchers, the rules have implications for many research fields, including gene therapy development.

Scientists often study biological processes, such as normal and mutant gene functions, in the worm Caenorhabditis elegans because it has many genes and molecular pathways in common with humans. Specific gene functions can be investigated by injecting DNA into the worm's reproductive organs, where it links into what is known as an extra-chromosomal array. This array is eventually incorporated into the nucleus, where it is duplicated and segregated into daughter cells. The injected genetic material is then potentially inherited across generations, which last only two days in C. elegans, allowing researchers to study gene functions over multiple generations in a short time period.

But C. elegans, like other multi-cellular organisms, has silencing mechanisms for recognizing and shutting down foreign DNA, which can hinder research efforts.

Scientists recently discovered that a class of noncoding DNA, called periodic A/T clusters (PATCs), can watermark their own genetic sequences to protect them from the natural silencing mechanisms of cells.

Bioengineer Christian Frøkjær-Jensen conducted investigations with students and researchers in his lab to develop rules for using PATCs, some gene regulators and reagents for persistent expression of transgenes in the C. elegans germline from simple extra-chromosomal arrays.

The protocol helps optimize transgenes and describes where PATCs should be inserted and the temperatures most suitable for propagating transgene strains, among other rules.

"Think of electrical circuits," says Frøkjær-Jensen. "Any electrical engineer can buy resistors and capacitors and be certain that these parts will behave in predictable ways when put together into a circuit. Our work aims to develop similar standards for genetic engineering in multicellular organisms. We also aim to freely distribute the necessary reagents for this process to the rest of the academic scientific community; we hope this will put KAUST on the map for biological engineering and synthetic biology."

Their investigations also led to the development of a web-based application for researchers to analyze their own DNA sequences for PATC watermarks. "PATCs can span large distances and rely on patterns that are not easily identifiable," explains Frøkjær-Jensen. "Previously, researchers needed to install specialized software to do this. Now, scientists can simply copy-paste their sequence files into our application to get an immediate analysis and graphical output." This will help scientists more easily use PATCs in their research and study their roles.
-end-
KAUST's web application for computing PATC scores in DNA sequences can be found at http://www.wormbuilder.org/PATC.

King Abdullah University of Science & Technology (KAUST)

Related Genetic Engineering Articles from Brightsurf:

Plant genetic engineering to fight 'hidden hunger'
More than two billion people worldwide suffer from micronutrient malnutrition due to deficiencies in minerals and vitamins.

Regulation of cancer stemness by the best combination of nanotech and genetic engineering
Photo-active nanocomplexes are successfully developed. The nanocomplexes allow spatiotemporal controlling genetically-engineered cells that are overexpressing temperature-sensitive membrane proteins.

Calculating genetic links between diseases, without the genetic data
In a new study, data scientists from the University of Chicago estimated heritability and mapped out relationships among thousands of diseases using data from electronic health records.

New CRISPR class expands genetic engineering toolbox
Biomedical engineers at Duke University have used a previously unexplored CRISPR technology to accurately regulate and edit target genes in human cells.

Engineering the meniscus
Damage to the meniscus is common, but there remains an unmet need for improved restorative therapies that can overcome poor healing in the avascular regions.

Artificially engineering the intestine
Short bowel syndrome is a debilitating condition with few treatment options, and these treatments have limited efficacy.

Scientists listed ways of applying genetic engineering to treat Parkinson's disease
Researchers of Sechenov University and University of Pittsburgh described the most promising strategies in applying genetic engineering for studying and treating Parkinson's disease.

Microbial manufacturing: Genetic engineering breakthrough for urban farming
Researchers at DiSTAP, SMART, MIT's research enterprise in Singapore, and National University of Singapore (NUS) have developed a new technology that revolutionises the creation of genetic material, enabling drastically accelerated genetic engineering of microbes that can be used to manufacture chemicals used for urban farming.

New genetic engineering strategy makes human-made DNA invisible
In a paper published recently in the Proceedings of the National Academy of Sciences journal, Dr.

With nanotubes, genetic engineering in plants is easy-peasy
Genetically modifying plants requires gene guns or bacteria to carry DNA into the cell, but the success rate is low.

Read More: Genetic Engineering News and Genetic Engineering Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.