Artemis,

Artemis and Its Crucial Role in DNA Damage Repair The human genome is constantly under siege, facing thousands of DNA lesions daily from environmental factors and normal cellular metabolism. Among these, DNA double-strand breaks (DSBs) are the most dangerous, potentially leading to cell death or cancer-driving mutations if not repaired correctly. While several proteins exist to manage this damage, the Artemis protein (encoded by the DCLRE1C gene) serves as a specialized endonuclease, acting as a crucial “molecular artisan” that trims and prepares broken DNA ends for repair. What is Artemis?

Artemis is a structure-specific endonuclease, part of the non-homologous end joining (NHEJ) pathway—the primary mechanism for repairing DSBs in human cells. Working closely with the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Artemis is activated to process complex, “dirty” DNA ends that are otherwise un-ligatable.

Beyond its role in DSB repair, Artemis is essential for V(D)J recombination, the process by which B and T lymphocytes generate a diverse repertoire of antibodies and receptors for the immune system. Crucial Roles in DNA Repair

Artemis is essential for maintaining genome integrity through several distinct mechanisms:

Processing Complex DSBs: When radiation or oxidative stress causes irregular, damaged ends in DNA, Artemis acts as an endonuclease to remove damaged nucleotides, allowing for successful repair.

Hairpin Opening in V(D)J Recombination: During immune system development, Artemis opens “hairpin” structures at the coding ends of DNA, a critical step for assembling functional immune receptors.

Cell Cycle Checkpoint Regulation: Emerging evidence shows that Artemis is phosphorylated by ataxia-telangiectasia mutated (ATM) kinase in response to damage, helping regulate cell cycle progression to prevent the replication of damaged DNA. The Impact of Artemis Deficiency

Mutations in the DCLRE1C gene, which encodes the Artemis protein, lead to a severe clinical phenotype.

Severe Combined Immunodeficiency (SCID): Because Artemis is essential for V(D)J recombination, its absence prevents the maturation of T and B lymphocytes.

Radiosensitivity: Artemis-deficient cells are highly sensitive to ionizing radiation because they cannot repair complex DNA breaks, leading to enhanced cell death upon radiation exposure.

Pathological Conditions: Patients with these mutations suffer from severe immune dysfunction combined with extreme sensitivity to environmental radiation. Artemis in Cancer Therapy and Prognosis

Recent research highlights the significant role of Artemis in oncology.

Resistance to Treatment: Overexpression of Artemis has been linked to increased resistance to chemotherapy and radiotherapy, as tumors use this protein to repair the damage inflicted by treatments.

Therapeutic Target: Because Artemis is required for repairing damage caused by ionizing radiation, it is considered a promising target for drug development. Inhibiting Artemis could potentially sensitize cancer cells to radiation or chemotherapy. Conclusion

Artemis is a foundational component of the cellular DNA damage response, specializing in the resolution of complex breaks within the NHEJ pathway and ensuring immune system diversity. Its dual role in both protecting the genome and aiding cancer resistance makes it a subject of intense research, offering new avenues for improving cancer treatments and understanding radiosensitivity. References Artemis and its role in cancer – PMC