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Leaky Scid phenotype associated with defective V(D)J coding end processing in Artemis-deficient mice.
Sean Rooney1, JoAnn Sekiguchi, Chengming Zhu
1Howard Hughes Medical Institute, The Children's Hospital, The Center for Blood Research, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA.
Molecular Cell
|December 31, 2002
Summary
Mutations in Artemis cause radiosensitive severe combined immune deficiency. Artemis-deficient mice mimic DNA-PKcs deficiency, highlighting Artemis
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Severe combined immune deficiency (SCID) in humans can result from mutations in the Artemis protein.
- Artemis, in conjunction with DNA-dependent protein kinase catalytic subunit (DNA-PKcs), exhibits DNA hairpin-opening activity in vitro.
- The V(D)J recombination process is crucial for adaptive immune system development and involves the joining of DNA coding ends.
Purpose of the Study:
- To investigate the in vivo function of Artemis in V(D)J recombination and DNA repair.
- To compare the phenotype of Artemis-deficient mice with that of DNA-PKcs-deficient mice.
- To elucidate the role of Artemis in maintaining genomic stability.
Main Methods:
- Generation and characterization of Artemis-deficient mice.
- Phenotypic analysis of Artemis-deficient mice, including immune cell populations and radiation sensitivity.
- Analysis of V(D)J recombination fidelity in Artemis-deficient and DNA-PKcs-deficient fibroblasts.
- Assessment of chromosomal stability in Artemis-deficient fibroblasts.
Main Results:
- Artemis-deficient mice exhibit severe combined immunodeficiency, impaired V(D)J coding hairpin end processing, and increased ionizing radiation sensitivity, similar to DNA-PKcs-deficient mice.
- Differences in V(D)J signal sequence joining fidelity between Artemis- and DNA-PKcs-deficient fibroblasts suggest distinct roles for DNA-PKcs.
- Artemis deficiency in fibroblasts leads to chromosomal instability, indicating a role in genomic maintenance.
Conclusions:
- Artemis functions with DNA-PKcs in specific non-homologous end joining (NHEJ) pathways essential for V(D)J recombination and DNA repair.
- DNA-PKcs possesses functions beyond those shared with Artemis, particularly in ensuring the fidelity of V(D)J signal sequence joining.
- Artemis acts as a genomic caretaker, and its deficiency compromises chromosomal stability.