Genomic Organization, Evolutionary Conservation and Expression of Ataxin-2 and Ataxin-2-like Genes Underscore the Suitability of Zebrafish as a Model Organism for SCA2 and Related Diseases.

Background/Objectives: The Ataxin-2 protein (ATXN2) plays an essential role in RNA metabolism and many cellular processes. Dysregulation or mutation of the Ataxin-2 gene (ATXN2) can lead to neurodegenerative diseases such as spinocerebellar ataxia type 2 (SCA2) and amyotrophic lateral sclerosis (ALS). Despite numerous efforts in this field in other animal models, little is known about Atxn2 in zebrafish. In this study, we aim to investigate the potential suitability of zebrafish as a model for Atxn2-related diseases by performing basic analyses on Atxn2. Methods: We performed a bioinformatic protein analysis of Atxn2 from zebrafish and its paralog Atxn2l in relation to human and other vertebrate homologues. Based on a structural analysis of the atxn2 and atxn2l genes, the expression of the predicted transcripts was detected by RT-PCR and the spatiotemporal expression pattern was determined by whole-mount in situ hybridization. Results: We found similarities between the protein sequences of Atxn2 and Atxn2l in zebrafish and their functional domains with those of orthologs in humans and other vertebrates. The predicted transcripts of atxn2 and atxn2l were experimentally verified and their spatiotemporal expression patterns were determined during zebrafish development. Splicing variants were detected for both genes, suggesting a different role for the isoforms in different tissues. Conclusions: These findings provide new insights into the atxn2 and atxn2l genes, suggesting the zebrafish as a suitable animal model for functional studies and research on disease modeling of SCA2 and ALS.