Expression of genes involved in soce in Danio rerio
INTRODUCTION: Store-Operated Calcium Entry (SOCE) is a major calcium influx mechanism in non‑excitable cells, however, there is increasing evidence indicating its significance in neurons. STIM proteins, that are calcium sensors localized in the endoplasmic reticulum membrane, are crucial for this process. Dysregulated calcium homeostasis is a feature of many neurodegenerative disorders. Recently, it was shown that the level of STIM2 is reduced in the hippocampus in mice model of Alzheimer’s disease (AD) and in cortical samples from sporadic AD patients. Moreover, expression of STIM2 in mice brain decreases with aging. AIM(S): The aim of this study was to determine the expression pattern of stims and orais in zebrafish. This will allow us to investigate Stim2 functions in neurons and to prepare models of some pathologies. Genetically modified zebrafish lines are often used as models of human diseases. METHOD(S): Using quantitative RT-PCR we estimated the mRNA level of stims and orais in larvae and in various tissues obtained from adult zebrafish. Using CRISPR/Cas9 technology stim2b‑/‑ zebrafish line was generated and then crossed with Tg(HuC:GCaMP5G) line. Changes in Ca2+ level in wild-type and k/o larvae were measured in vivo using Light-Sheet microscopy with GCaMP5G calcium probe expressed in neurons. RESULTS: Similarly to what was observed in rodents, orai2 dominates in the brain, nevertheless, there are some differences between mammalian and zebrafish expression pattern regarding stims. It was shown that Stim2 is mainly expressed in the mouse brain, while in zebrafish both stim2 isoforms dominate in muscles, however their level in the brain is still relatively high. Interestingly, stim1b and stim2b as well as orai1a and orai1b expression significantly increases with aging. CONCLUSIONS: The analysis of calcium homeostasis and gene expression in stim2b‑/‑ fish indicates that this calcium ER sensor plays an important role in zebrafish neurons.