THU079 Danio Rerio (Zebrafish): A New Model Of AIP Loss Of Function

Abstract

Abstract Disclosure: X. Wang: None. A. Leggieri: None. S. Anagianni: None. C.H. Brennan: None. M. Korbonits: None. Background: Mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene account for 10% of cases with familial isolated pituitary adenoma (FIPA). The main features of patients carrying heterozygous AIP mutations include young-onset, large and invasive growth hormone and/or prolactin-secreting pituitary tumours, although a milder spectrum of presentation has been also described. In several animal models (mouse, fruit fly, round worm), homozygous deletion of AIP results in embryonic mortality. In mice abnormal cardiac development has been observed. Objective: The aim of this study was to generate a zebrafish loss-of-function model to explore the cellular biological processes affected by heterozygous or homozygous aip mutations. Methods: Zebrafish homologue of human AIP was identified by EMBOSS Needle program. We used CRISPR/Cas9 to generate a line of fish carrying loss-of-function mutations targeting zebrafish aip exon 2. aip RNA expression was examined using in situ hybridisation. The growth rate and cardiac function were assessed using a stereo microscope with an integrated camera. The videos and pictures were analysed in ImageJ. Antisense in situ hybridisation with probes to growth hormone 1 (gh1), prolactin (prl) and proopiomelanocortin a (pomca) was used to assess pituitary phenotypes. Results: Zebrafish aip shows 78.8% of homology to human AIP. aip mRNA is expressed throughout the developing zebrafish embryo until 28 hours post fertilisation (hpf) stage when it becomes more strongly expressed in the head. We generated a 29 bp deletion in exon 2 of the zebrafish aip gene. These mutant animals showed reduced aip expression. No significant gross morphology differences were observed at 3 to 7 days post fertilisation (dpf) between wildtype (WT) and heterozygote (Het) animals. At 5dpf, WTs showed an increased heart rate than Hets (P=0.033). Conclusion: We have generated an aip loss of function zebrafish line that provides an ideal opportunity to analyse the role of aip in development. Presentation: Thursday, June 15, 2023