N-terminal RAG1 frameshift mutations in Omenn's syndrome: Internal methionine usage leads to partial V(D)J recombination activity and reveals a fundamental role in vivo for the N-terminal domains

Sandro Santagata, Carlos A. Gomez, Cristina Sobacchi, Fabio Bozzi, Mario Abinun, Srdjan Pasic, Patricia Cortes, Paolo Vezzoni, Anna Villa

Research output: Contribution to journalArticlepeer-review

Abstract

Omenn's syndrome is an autosomal recessive primary immunodeficiency characterized by variable numbers of T lymphocytes of limited clonality, hypereosinophilia, and high IgE levels with a paradoxical absence of circulating B lymphocytes. We have previously attributed this disorder to missense mutations that render the RAG1/RAG2 recombinase only partially active. Here we report seven Omenn's patients with a novel class of genetic lesions: frameshift mutations within the 5′ coding region of RAG1. Interestingly, we demonstrate in transient expression experiments that these frameshift deletion alleles remain partially functional for both deletional and inversional recombination and can hence explain the partial rearrangement phenotype observed in these patients. The rearrangement activity is mediated by truncated RAG1 proteins that are generated by alternative ATG usage 3′ to the frameshift deletion and that demonstrate improper cellular localization. Taken together, our results suggest a novel mechanism for the development of immunodeficiency in a subset of Omenn's syndrome patients.

Original languageEnglish
Pages (from-to)14572-14577
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume97
Issue number26
DOIs
Publication statusPublished - Dec 19 2000

ASJC Scopus subject areas

  • Genetics
  • General

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