Effects of changes in TIA1 on stress granule formation

Welander Distal Myopathy (WDM) is caused by the p.E384K mutation in the TIA1 gene. The mutation supposedly causes the disease by a gain-of-function mechanism related to the formation of stress granules (Hackman et al. 2013). Also environmental factors have been proposed to affect the development of the disease: an increased number of stress granules has been observed in cells treated with cold shock compared to cells kept in 37 °C (Hofmann et al. 2012). When patients with WDM-like symptoms have been screened for changes in TIA1, an p.N357S-change has been found enriched in these patients. The p.N357S-change has earlier been reported as a polymorphism. The change in question is located in the same prion-like domain in exon 5, in which the p.E384K-mutation also lies. Therefore, the p.N357S-change could affect the predisposition to aggregation. The pro gradu project is divided into two parts: • The effect of the p.N357S polymorphism on stress granule formation in arsenite and possibly other stress treated cells • The effect of cold shock on stress granule formation on wild type and p.E384K TIA1 The results indicate, that the p.N357S change in TIA1 causes a change in the translated protein’s behavior. Similarly to the p.E384K change, the p.N357S change also induces an increased amount of stress granules in arsenite treated cells. However, the results also show that the stress granules recover faster in fluorescence recovery after photobleaching (FRAP) studies p.N357S transfected cells as compared to TIA1 p.E384K and wild type transfected cells. The cold shock experiment indicates that there is a difference in the stress granule formation between cells transfected with p.E384K and wild type TIA1. This supports previously published results of the effect of the p.E384K change on the stress response and stress granule formation, and also the use of cold shock as a stress inducing treatment. Used methods: PCR, transformation, DNA-extraction, cell culture, transfection, induction of stress granule formation by arsenite treatment and cold shock. The cells are cultivated on well plates, imaged and the data is analyzed with an automatized high content image analysis method (the CellInsight-platform). p.N357S cells were also analyzed with FRAP.