Abstract: Objective To analyze the association of staphylococcal nuclease domain-containing protein 1(SND1) and T-cell intracellular antigen 1(TIA-1) on stress granules, and the regulation of SND1 on stress granules under stress stimuli. Methods The immunofluorescence assay and laser scanning confocal microscopy were used to observe the co-localization of SND1 protein and TIA-1 protein under stress stimuli, and the over-expression plasmids of pEGFP vector were transfected into HeLa cells and to verify which domain of SND1 co- localized with TIA- 1 under stress stimuli. RNA interferencemediated knockdown of the expression of SND1 protein in HeLa cells was measured by Western Blotting assay. Then whether the knockdown of SND1 affected the recruitment of TIA- 1 on stress granules was observed. Heat shocks under different times were used to identify whether there were dynamic changes in transportation of SND1 and TIA-1 on stress granules. Results SND1 co-localized with TIA- 1 on stress granules under stress stimuli, and the associated domain of SND1 were SN domain. TIA-1 still can be recruited on stress granules but a large amount of stress granules were reduced even though the expression of SND1 protein was decreased. And the transportation of SND1 on stress granules was laged behind TIA-1 under different-times of heat shocks. Conclusion SND1 protein co-localizes with TIA-1 on stress granules, and which co-regulates the cellular stress response under stress stimuli.

Key words: stress, RNA interference, Staphylococcal nuclease domain- containing protein 1, T- cell intracellular antigen 1, stress granule