Mechanisms of an autoimmunity syndrome in mice caused by a dominant mutation in Aire
Maureen A. Su, Karen Giang, Kristina Žumer, Huimin Jiang, Irena Oven, John L. Rinn, Jason J. DeVoss, Kellsey P.A. Johannes, Wen Lu, James Gardner, Angela Chang, Paula Bubulya, Howard Y. Chang, B. Matija Peterlin, Mark S. Anderson
Maureen A. Su, Karen Giang, Kristina Žumer, Huimin Jiang, Irena Oven, John L. Rinn, Jason J. DeVoss, Kellsey P.A. Johannes, Wen Lu, James Gardner, Angela Chang, Paula Bubulya, Howard Y. Chang, B. Matija Peterlin, Mark S. Anderson
View: Text | PDF
Research Article Autoimmunity

Mechanisms of an autoimmunity syndrome in mice caused by a dominant mutation in Aire

Abstract

Homozygous loss-of-function mutations in AIRE cause autoimmune polyglandular syndrome type 1 (APS 1), which manifests in a classic triad of hypoparathyroidism, adrenal insufficiency, and candidiasis. Interestingly, a kindred with a specific G228W AIRE variant presented with an autosomal dominant autoimmune phenotype distinct from APS 1. We utilized a novel G228W-knockin mouse model to show that this variant acted in a dominant-negative manner to cause a unique autoimmunity syndrome. In addition, the expression of a large number of Aire-regulated thymic antigens was partially inhibited in these animals, demonstrating the importance of quantitative changes in thymic antigen expression in determining organ-specific autoimmunity. Furthermore, the dominant-negative effect of the G228W variant was exerted through recruitment of WT Aire away from active sites of transcription in the nucleus of medullary thymic epithelial cells in vivo. Together, these results may demonstrate a mechanism by which autoimmune predisposition to phenotypes distinct from APS 1 can be mediated in a dominant-negative fashion by Aire.

Authors

Maureen A. Su, Karen Giang, Kristina Žumer, Huimin Jiang, Irena Oven, John L. Rinn, Jason J. DeVoss, Kellsey P.A. Johannes, Wen Lu, James Gardner, Angela Chang, Paula Bubulya, Howard Y. Chang, B. Matija Peterlin, Mark S. Anderson

×

Figure 7

The G228W protein acts in a dominant-negative fashion to inhibit localization of Aire to sites of active transcription.

Options: View larger image (or click on image) Download as PowerPoint
The G228W protein acts in a dominant-negative fashion to inhibit localiz...
(A and B) Immunohistochemistry of Aire+/+ (A) and AireGW/+ (B) thymi stained with the indicated nuclear marker (green; left columns), anti-Aire antibody (red; middle columns) and DAPI (blue). Arrows indicate nuclear inclusion bodies. Scale bar: 3.17 μm. (C) Coimmunoprecipitation of G228W and WT AIRE. myc-tagged WT AIRE (m.AIRE WT), G228W AIRE (m.AIRE GW), and/or FLAG-tagged G228W AIRE (f.AIRE GW) were transfected into 1C6 cells, immunoprecipitated with anti-FLAG antibody, and subjected to Western blotting with either anti-myc (top row) or FLAG antibody (second row). To ensure protein expression, 10% of lysates were blotted with anti-myc (third row) or anti-FLAG (fourth row) antibody. (D) Insulin promoter activation by G228W and WT AIRE. m.AIRE WT, f.AIRE GW, or both (GW/WT of 1:5, 1:2, and 1:1 in columns 3–5, respectively) were transfected with the HIP339Luc insulin promoter–luciferase reporter into 1C6 cells. Protein expression using anti-FLAG (top row), anti-myc (middle row), or anti-GAPDH (bottom row) is shown by Western blot. (E) Chromatin immunoprecipitation of 1C6 cells transfected with empty vector (vector), WT AIRE (WT), G228W AIRE (GW), or the latter 2 in combination (WT+GW) with anti-AIRE antibody (black bars) or isotype control (white bars). Average amount (±SD) of mouse insulin 2 promoter (normalized as percentage of input) in the immunoprecipitates is shown. Relative amounts of AIRE input and GAPDH (loading control) are shown by Western blot (bottom panel). Measurements were done in triplicate in 2 independent experiments, with results of a representative experiment shown.