In vivo bioassay to test the pathogenicity of missense human AIP variants

Elena Daniela Aflorei; Benjamin Klapholz; Chenghao Chen; Serban Radian; Anca Neluta Dragu; Nina Moderau; Chrisostomos Prodromou; Paulo S Ribeiro; Ralf Stanewsky; Márta Korbonits

doi:10.1136/jmedgenet-2017-105191

In vivo bioassay to test the pathogenicity of missense human AIP variants

J Med Genet. 2018 Aug;55(8):522-529. doi: 10.1136/jmedgenet-2017-105191. Epub 2018 Apr 9.

Authors

Affiliations

¹ Centre for Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, UK.
² Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
³ Department of Cell and Developmental Biology, Division of Biosciences, Faculty of Life Sciences, University College London, London, UK.
⁴ Department of Endocrinology, C.I. Parhon National Institute of Endocrinology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
⁵ Protein Dynamics and Cell Signalling Laboratory, Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, UK.
⁶ Genome Damage and Stability Centre, University of Sussex, Brighton, UK.
⁷ Institute of Neuro- and Behavioural Biology, Westfälische Wilhelms University, Münster, Germany.

Abstract

Background: Heterozygous germline loss-of-function mutations in the aryl hydrocarbon receptor-interacting protein gene (AIP) predispose to childhood-onset pituitary tumours. The pathogenicity of missense variants may pose difficulties for genetic counselling and family follow-up.

Objective: To develop an in vivo system to test the pathogenicity of human AIP mutations using the fruit fly Drosophila melanogaster.

Methods: We generated a null mutant of the Drosophila AIP orthologue, CG1847, a gene located on the Xchromosome, which displayed lethality at larval stage in hemizygous knockout male mutants (CG1847^exon1_3 ). We tested human missense variants of 'unknown significance', with 'pathogenic' variants as positive control.

Results: We found that human AIP can functionally substitute for CG1847, as heterologous overexpression of human AIP rescued male CG1847^exon1_3 lethality, while a truncated version of AIP did not restore viability. Flies harbouring patient-specific missense AIP variants (p.C238Y, p.I13N, p.W73R and p.G272D) failed to rescue CG1847^exon1_3 mutants, while seven variants (p.R16H, p.Q164R, p.E293V, p.A299V, p.R304Q, p.R314W and p.R325Q) showed rescue, supporting a non-pathogenic role for these latter variants corresponding to prevalence and clinical data.

Conclusion: Our in vivo model represents a valuable tool to characterise putative disease-causing human AIP variants and assist the genetic counselling and management of families carrying AIP variants.

Keywords: AIP; FIPA; drosophila melanogaster; pathogenic genetic variant; pituitary adenoma.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Alleles
Amino Acid Sequence
Amino Acid Substitution
Animals
Animals, Genetically Modified
Biological Assay
Drosophila melanogaster
Female
Gene Expression
Genetic Association Studies* / methods
Genetic Predisposition to Disease*
Genetic Testing
Genotype
Humans
Intracellular Signaling Peptides and Proteins / chemistry
Intracellular Signaling Peptides and Proteins / genetics*
Loss of Function Mutation
Loss of Heterozygosity
Male
Models, Molecular
Mutation, Missense*
Pituitary Neoplasms / diagnosis
Pituitary Neoplasms / genetics
Protein Conformation
Structure-Activity Relationship

Substances

Intracellular Signaling Peptides and Proteins
aryl hydrocarbon receptor-interacting protein

Abstract

Publication types

MeSH terms

Substances

Grants and funding