Scientist from Icahn School of Medicine have been able to simultaneously evaluate the functions of hundreds of genes with resolution reaching single-cell level using a newly developed novel Genetic Barcoding technology. The study, featured in the recent issue of journal Cell, describes the new technology that relies on barcoding approach using a specific protein.
Although the sequencing of human genome was pioneered by scientists in the early 2000s, revealing a set of over 20,000 protein-coding genes, various functions of an individual gene had remained unknown. As a result, it limited the understanding of working of human genome and how it can be used to detect, prevent, and cure a disease.
At time period between 2012 and 2013, scientists developed a powerful approach for editing genes, known as CRISPR (clustered regularly interspaced short palindromic repeats) that can be used to identify many functions of the genes. It was one of the major scientific breakthroughs but scientists continue to face several challenges with using CRISPR such as the inability to study a multitude of genes and their innumerable possible roles.
The recently developed Genetic Barcoding technology, however, could address the challenge for analyzing genome functions at a remarkable scale. According to Maxime Dhainaut, Ph.D. and Aleksandra Wroblewska, Ph.D. who led the research team, they have created a novel tool that can barcode and track a record of various CRISPRs using epitopes, a synthetic protein. Termed as Pro-codes, the protein barcodes allow huge number of CRISPRs to be used together to eliminate a large group of genes.
Although there have been technologies for pooling CRISPRs, the new approach rely extremely on DNA as a barcode and allow only low resolution look into gene function. According to the researchers, the Pro-Code technique provides a way for scientists to characterize the biologic effects of a gene to a greater extent. Further, they used the new technology to discover genes for the immune system to protect from complex diseases such as cancer.
In the study, the researchers generated CRISPRs to target the deletion of suspected genes responsible for immune regulation, and paired them with the Pro-codes. While the Pro-code libraries were introduced to cancer cells, the tumors were targeted with killer T-cells that had been maneuvered to detect the cancer cells. The T-cells rapidly knocked out majority of the cancer cells, while some cells have completely resisted death. The novel technology helped to determine the loss of genes through the resistant cells and a major clinical target of cancer immunotherapy – a negative regulator for the immune checkpoint PD-L1.
As reported in Medical Express, the Pro-code technology could greatly accelerate annotation of the human genome which has been one of the goals of the post-genome era, citing a senior author Brian Brown, Ph.D. It gives new insights in cancer immunology and is a key to search disease-causing genes that could result into novel drug targets, he said.