Drosophila melanogaster as a model organism to study aryl hydrocarbon receptor interacting protein gene function

Elena Daniela Aflorei; ghao Chen; Benjamin Klapholz; Ashley B Grossman; Nicolas Tapon; Nicholas H Brown; Ralf Stanewsky; Marta Korbonits

doi:10.1530/endoabs.32.P825

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Endocrine Abstracts (2013) 32 P825 | DOI: 10.1530/endoabs.32.P825

ECE2013 Poster Presentations Pituitary–Basic (<emphasis role="italic">Generously supported by IPSEN</emphasis>) (17 abstracts)

Drosophila melanogaster as a model organism to study aryl hydrocarbon receptor interacting protein gene function

Elena Daniela Aflorei ¹ , Chenghao Chen ² , Benjamin Klapholz ³ , Ashley B Grossman ⁴ , Nicolas Tapon ⁵ , Nicholas H Brown ³ , Ralf Stanewsky ² & Márta Korbonits ¹

Err

Author affiliations

¹Department of Endocrinology, Barts and the London School of Medicine, Queen Mary University of London, London, UK; ²School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK; ³Department of Physiology, Development and Neuroscience, The Gurdon Institute, University of Cambridge, Cambridge, UK; ⁴Department of Clinical Oncology, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK; ⁵Apoptosis and Proliferation Control Laboratory, Cancer Research UK, London Research Institute, London, UK.

Introduction: Loss-of-function mutations in AIP are associated with familial isolated pituitary adenoma, often leading to gigantism due to invasive GH-secreting pituitary adenomas. One challenging problem in the management of patients carrying a missense AIP variant is to determine whether the missense variant is a disease-causing mutation or not. As most of the molecular mechanisms involved in the control of growth and the cell cycle are well-conserved, we propose to utilise the fruitfly to determine putative disease-causing human variants. The Drosophila melanogaster AIP orthologue gene CG1847 codes for a protein with a similar size and structure.

Methods: We created CG1847 deficiency either via RNAi knockdown (using two different RNAi-lines) or via knocking out with the help of imprecise excision of a P-element located inside the 5′-UTR of CG1847 gene.

Results: When a universal driver (actin) was used to express the CG1847 RNAi, no viable adult offspring were observed, indicating that complete AIP-knockdown is lethal. To confirm these results with a different approach, we generated imprecise excisions of a P-element and deletion of a 1497 bp fragment, creating a loss-of-function mutation of Drosophila AIP (CG1847^exon1,2). This mutant is lethal in males (females are viable being heterozygotes for this CG1847^exon1,2 mutation).

Conclusions: We have demonstrated that total deficiency of CG1847 leads to lethality in fruitfly similar to results in AIP-KO mice, confirming that CG1847 is an essential gene for fly development. In our future experiments we will attempt to rescue the fruitfly CG1847^exon1,2 mutant with human AIP, and then we will make mutants containing different human AIP missense variants. These experiments should ultimately test the degree of functional conservation between fly and human, and help to determine whether the missense variant is likely to be a disease-causing mutation or not.