The regulation of mRNA stability is an important step of gene expression. AU-rich elements (AREs) in 3´ untranslated regions are of special interest due to their presence in many short-lived mRNAs including cytokine, proto-oncogene and growth factor mRNAs. HuR, initially identified as an autoimmune antigen and recently as a prognostic factor for ovarian carcinoma, is capable of stabilizing many short-lived mRNAs in ARE-mediated way. In order to verify the endogenous association between HuR and cytokine mRNA, polysome lysates were prepared from BJAB cells and then HuR-bound mRNAs were immunoprecipitated using monoclonal anti-HuR antibody. This subset of mRNAs contained TNF-α mRNA as well as other mRNAs previously identified in a similar way.