Glossaire

Cas9 nuclease is a molecular tool derived from the bacterial defense mechanism known as the CRISPR-Cas system. In bacteria, Cas nucleases, such as Cas9, protect against viral infection by cutting, and thereby destroying, viral DNA. Due to its capacity to precisely cut double-stranded DNA, Cas9 nuclease is often referred to as molecular scissors. It is widely used in genome editing applications, allowing scientists to make precise modifications to the DNA of various organisms for research, therapeutic, and biotechnological purposes.

The DNA cutting process is initiated by the formation of a complex (a functional unit) of Cas9 with a short RNA sequence known as guide RNA (gRNA). The complex, known as ribonucleoprotein, then scans the DNA for a complementary match between gRNA and DNA sequences. At the precise match site, Cas9 cuts both strands of the double-stranded DNA, introducing double-stranded DNA breaks. These break sites can be used for silencing an unwanted gene function or for the introduction of new genes into the organism. The break sites in the DNA are corrected and bound together by the cell's DNA repair mechanism, which is activated upon detection of DNA breaks.
 

Chimeric Antigen Receptor (CAR) is a designed receptor (a protein which detects a signal) used in immunotherapy, particularly in the field of gene therapy. CAR is a synthetic receptor that combines components from different proteins. It is able to recognize a specific antigen on the surface of target cells, often cancer cells. After introducing the CAR inside the cell employing a gene vector, the CAR-bearing cells, such as hematopoietic stem cells or immune cells, can more effectively and specifically identify and attack cells displaying the targeted antigens to initiate a precise response against the disease.

Chromosomes are thread-like structures composed of DNA and proteins, found in the nucleus of a cell. Chromosomes carry genetic information in the form of genes that serve as instruction to produce proteins for building and maintaining the body. Humans typically have 23 pairs of chromosomes (46 in total) in each somatic cell. Gametes (egg and sperm cells) contain only a single chromosome set.

A clinical trial is a supervised research study where doctors and scientists evaluate the safety and effectiveness of a new medical treatment. In clinical trials, volunteers receive the investigational treatment and are monitored by researchers who collect data on the treatment's potential benefits and risks. Clinical trials are essential for ensuring patient safety and improving current healthcare options. 

The CRISPR-Cas system is a genome editing tool widely used in genome editing. The system was originally discovered as a bacterial defense mechanism that bacteria use to recognize and cut foreign DNA sequences (for example those of bacteriophages). The system works by a combination of a guide RNA that delivers the system to the correct area in the DNA and molecular scissors, called Cas nuclease, which cuts DNA at the specific site. Since its discovery, scientists have harnessed the biological system as a tool to add, remove, and replace genetic information, allowing us to understand how genes work and develop new treatments for diseases.