Researchers state that this technique will increase the efficiency of laboratory research and expand the scope of gene therapy. Artificial human chromosomes that function in human cells have the potential to revolutionize gene therapy, including the treatment of some cancers, and have numerous laboratory applications. However, significant technical problems hindered their progress.

Now, a team led by researchers at the University of Pennsylvania Perelman School of Medicine has made a major breakthrough in this field, effectively overcoming a common barrier.

In a recently published study ScienceThe researchers described how they developed an effective technique to create HACs from single long structures of designer DNA. Previous methods of creating HACs were limited in that the DNA structures used to create them tended to come together (“multimerize”) in unpredictable long term and with unpredictable rearrangements. The new method enables faster and more accurate generation of HACs, which will directly increase the speed of DNA research. Over time, with an effective delivery system, this technique could lead to better cell therapy for diseases such as cancer.

Revision by HAC Design

Eldridge Reeves Johnson Foundation Professor of Biochemistry and Biophysics at Penn, Ph.D. “In fact, we have completely revolutionized the legacy approach to HAC design and deployment,” said Ben Black. “The HAC we created is very attractive for possible deployment in biotechnological applications, such as where large-scale genetic engineering of cells is required. The bonus is that they exist alongside native chromosomes without having to replace the native chromosomes in the cell.”

The first HACs were developed 25 years ago, and artificial chromosome technology is already well developed for the smaller, simpler chromosomes of lower organisms such as bacteria and yeast. Human chromosomes are a different matter because of their larger size and more complex centromeres, the central region where the arms of X-like chromosomes meet. Researchers have managed to create small artificial human chromosomes from the self-assembly of DNA inserted into cells, but these pieces of DNA multimerize with unpredictable organization and copy number, making them difficult to use therapeutically or scientifically, and as a result HAC sometimes ends up on the line. they contain fragments of natural chromosomes from their host cells, making their arrangement unreliable.

In their study, Penn Medicine researchers developed improved HACs with several innovations: These included larger starting DNA structures with larger and more complex centromeres, allowing HACs to form from individual copies of these structures. They used a yeast cell-based delivery system that can carry larger cargos for delivery into cells.

“For example, instead of trying to suppress multimerization, we circumvented the problem by increasing the size of the input DNA structure so that it remained in its naturally predicted single-copy form,” Black said.

The researchers showed that their method was much more effective than standard methods in creating viable HACs and produced HACs that could proliferate during cell division.

Advantages and future applications

Artificial chromosomes have many potential benefits, provided they can be easily delivered to cells and function like natural chromosomes. Unlike virus-based gene delivery systems, which can trigger immune responses and involve the introduction of a harmful virus into native chromosomes, they may offer safer, more productive and longer-lasting platforms for the expression of therapeutic genes. Normal gene expression in cells also requires many local and remote regulatory factors that are almost impossible to replicate artificially outside the chromosomal context. In addition, artificial chromosomes, unlike relatively narrow viral vectors, will allow the expression of large cooperative gene ensembles, for example, the creation of complex protein machines.

Black hopes that the same broad approach his group used in this study will be useful for creating artificial chromosomes in other higher organisms, including plants for agricultural applications such as pest-resistant, high-yielding crops.