Human Tudor-SN Protein Function In The Formation Of RNA Granules

Objectives:Human Tudor-SN protein is a ubiquitously expressed, multifunctional RNA-binding protein involved in various kinds of biological processes. SGs are mRNA containing cytoplasmic structures that are assembled in response to stress. Tudor-SN has been found to physiologically interact with G3BP in the same SGs in response to different stress stimuli.Our project aims at the study of Tudor-SN protein assembly onto SGs and Processing-bodies and its mechanism of post-transcriptional gene regulation.Methods:Our project includes four experimental parts. In Part I, we study the assembly of Tudor-SN onto SGs and its colocalization with TIA-1under stress condition by immunoflourescence staining. In Part II, we study the recruitment of Tudor-SN onto P-bodies and its colocalization with P-bodies components:Ago2and Dcpl. In Part III, we study whether knockdown of endogenous Tudor-SN protein could affect the formation of SGs by RNAi mechanism. In Part IV, we study the kinetic recruitment and transportation of Tudor-SN onto SGs by immunoflourescence.Results:1. The assembly of Tudor-SN protein onto SGs is mediated by its SN domain in response to stress. Recruitment, of Tudor-SN onto SGs lags behind TIA-1.2. Tudor-SN protein can assemble onto P-bodies and colocalizes with Ago2and Dcpl under same stress stimuli.3. Knockdown of endogenous Tudor-SN protein did not inhibit the formation of SGs but decrease the size and density of SGs.4. The kinetic recruitment of Tudor-SN protein onto SGs is dependent on a-Tubulin, a Microtubule protein.Conclusions:These findings identify Tudor-SN is a key component recruited onto SGs as well as to P-bodies. It can colocalize with TIA-1, Ago2and Dcpl separately under the same stress conditions. The assembly of Tudor-SN onto SGs is dependent on a-Tubulin. However, Tudor-SN may not be as essential as G3BP to initiate the formation of SGs but affect the aggregation of SGs.