Defective artemis nuclease is characterized by coding joints with microhomology in long palindromic-nucleotide stretches

Van der Burg M., Verkaik N. S., den Dekker A. T., Barendregt B. H., Pico-Knijnenburg I., Tezcan I., ...More

EUROPEAN JOURNAL OF IMMUNOLOGY, vol.37, no.12, pp.3522-3528, 2007 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 37 Issue: 12
  • Publication Date: 2007
  • Doi Number: 10.1002/eji.200737624
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.3522-3528
  • Hacettepe University Affiliated: Yes


T-B-NK+ severe combined immunodeficiency (SCID) is caused by a defect in V(D)J recombination. A subset of these patients has a mutation in one of the non-homologous end joining (NHEJ) genes, most frequently the Artemis gene. Artemis is involved in opening of hairpin-sealed coding ends. The low levels of residual D-H-J(H) junctions that could be amplified from patients' bone marrow precursor B cells showed high numbers of palindromic (P)-nucleotides. In 25% of junctions, microhomology was observed in the P-nucleotide regions, whereas this phenomenon was never observed in junctions amplified from bone marrow precursor B cells from healthy controls. We utilized this difference between Artemis-deficient cells and normal controls to develop a V(D)J recombination assay to determine hairpin-opening activity. Mutational analysis of the Artemis gene confirmed and extended the mapping of an N-terminal nuclease active site, which contains several indispensable aspartate residues. C-terminal deletion mutants did not show such severe defects in the V(D)J recombination assay using transient overexpression of (mutated) Artemis protein. However, a C-terminal deletion mutation causes T-B-NK+ SCID, indicating that the Artemis C terminus is essential for V(D)J recombination at the normal Artemis expression level. The V(D)J recombination assays used in this study contribute to the diagnostic strategy for T-B-NK+ SCID patients.