Identification of RNA binding proteins that interact with AU-rich elements of Lif 3`UTR

Leukemia inhibitory factor (LIF) is an important endogenous factor for photoreceptor protection. Lif is known to be upregulated both in induced and inherited disease models of photoreceptor degeneration only in a subset of Muller cells. Since Lif is induced in Muller cells in response to photoreceptor injury, we studied its regulation in Muller cells. We have recently identified several AU-rich elements (AREs) within the 3′ untranslated region (UTR) of Lif . We also showed that as a result of these elements Lif encodes a highly unstable mRNA. mRNAs containing AREs in the 3`UTR undergo rapid ARE-mediated mRNA decay in the cytoplasm which is mediated by the RNA–binding proteins. In order to identify the RNA-binding proteins that are involved in the regulation of Lif transcripts, we will use the biotin-labelled RNA. By using this methodology, we will isolate the related RNA binding proteins. We plan to analyze the isolated proteins by mass spectrometry, and compare the mass spectrometry results of different regions with or without AREs . Once we identify the specific proteins that bind only to AREs, we will do the functional characterization of these proteins by cotransfecting the constructs with AREs and the siRNA that inhibits the expression of related RNA binding protein.