Disease-associated AIOLOS variants lead to immune deficiency/dysregulation by haploinsufficiency and redefine AIOLOS functional domains
Hye Sun Kuehn, … , Svetlana O. Sharapova, Sergio D. Rosenzweig
Hye Sun Kuehn, … , Svetlana O. Sharapova, Sergio D. Rosenzweig
Published November 28, 2023
Citation Information: J Clin Invest. 2024;134(3):e172573. https://doi.org/10.1172/JCI172573.
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Research Article Immunology

Disease-associated AIOLOS variants lead to immune deficiency/dysregulation by haploinsufficiency and redefine AIOLOS functional domains

Abstract

AIOLOS, also known as IKZF3, is a transcription factor that is highly expressed in the lymphoid lineage and is critical for lymphocyte differentiation and development. Here, we report on 9 individuals from 3 unrelated families carrying AIOLOS variants Q402* or E82K, which led to AIOLOS haploinsufficiency through different mechanisms of action. Nonsense mutant Q402* displayed abnormal DNA binding, pericentromeric targeting, posttranscriptional modification, and transcriptome regulation. Structurally, the mutant lacked the AIOLOS zinc finger (ZF) 5–6 dimerization domain, but was still able to homodimerize with WT AIOLOS and negatively regulate DNA binding through ZF1, a previously unrecognized function for this domain. Missense mutant E82K showed overall normal AIOLOS functions; however, by affecting a redefined AIOLOS protein stability domain, it also led to haploinsufficiency. Patients with AIOLOS haploinsufficiency showed hypogammaglobulinemia, recurrent infections, autoimmunity, and allergy, but with incomplete clinical penetrance. Altogether, these data redefine the AIOLOS structure–function relationship and expand the spectrum of AIOLOS-associated diseases.

Authors

Hye Sun Kuehn, Inga S. Sakovich, Julie E. Niemela, Agustin A. Gil Silva, Jennifer L. Stoddard, Ekaterina A. Polyakova, Ana Esteve Sole, Svetlana N. Aleshkevich, Tatjana A. Uglova, Mikhail V. Belevtsev, Vladislav R. Vertelko, Tatsiana V. Shman, Aleksandra N. Kupchinskaya, Jolan E. Walter, Thomas A. Fleisher, Luigi D. Notarangelo, Xiao P. Peng, Ottavia M. Delmonte, Svetlana O. Sharapova, Sergio D. Rosenzweig

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Figure 3

The effect of AIOLOS Q402* on homo- and heterodimerization with IKAROS family members.

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The effect of AIOLOS Q402* on homo- and heterodimerization with IKAROS f...
(A) HEK293T cells were transfected with HA-tagged AIOLOS WT or the mutant (Q402*) together with Flag-tagged AIOLOS WT. Immunoprecipitations were performed as indicated in the figure using an anti-rabbit Flag antibody or anti-rabbit IgG control antibody. Western blot data of the IP samples with anti-HA and anti-Flag antibodies are shown. Input controls indicate 5% of the total volumes of the whole cellular lysates used for the IP reaction. (B) HEK293T cells were transfected with HA-tagged AIOLOS WT or the mutant together with Flag-tagged AIOLOS WT, IKAROS WT (left panel), or HELIOS WT (right panel). Cell lysates were subjected to immunoprecipitations using anti-rabbit HA antibody or anti-rabbit IgG control. Western blot data of the IP samples with indicated antibodies are shown. (C) NIH3T3 cells were transfected with HA-tagged AIOLOS WT or the mutant together with Flag-tagged IKAROS WT (left panel) or HELIOS WT (right panel). Cells were labeled with anti-mouse HA and anti-rabbit Flag antibodies, followed by Alexa Fluor 488-conjugated and/or Alexa Fluor 568-conjugated secondary antibodies, respectively. Cells were visualized using an EVOS (40× objective) fluorescent microscope. Scale bars: 25 μm. Data (A–C) shown are representative of 3 independent experiments.