The Function Of RNA Binding Protein-ILF3in The Estrogen Signaling Transduction

Recently, the function of mRNA untranslated region (UTR) is one of the hotspots inbiological research. There are many regulatory elements in the3’UTR of mRNA sequences.Proteins and protein complex interact with these regulatory elements, which may play animportant role in regulating the translation of mRNA, the stability of mRNA, subcellularlocalization and so on. ER beta was important on the occurrence and development in thebreast, prostate cancer, colon cancer and ovarian cancer. By the technology of RNApull-down,we found a protein which can bind the ERbeta3’UTR.This protein is ILF3, whichhas a special affinity for AU-rich sequence of the mRNAs. The research for functions of ILF3has great meaning for studying the regulation mechanisms which are related to the3’UTR ofER beta.Interleukin enhancer-binding factor3(ILF3) is one of member of double-strandedRNA-binding proteins, which the gene mapped in the human Chromosome19, coding by ilf3gene. ILF3participates in cell cycle control, RNA transcription, RNA splicing, RNA editing,nuclear transport, subcellular localization. It also involves in the multiple cellular functionsincluding cell development, cell cycle and viral infection.In this thesis, we used Western Blot, Electrophoretic Mobility Shift Assay（EMSA）toconfirm a conclustion. ILF3can specifically bind to ER beta mRNA3’UTR. Estrogen ismediated by estrogen receptor to achieve its function, ILF3interact with ER beta mRNA3’UTR, ILF3may be involved in the regulation of estrogen signaling pathway. In order toreveal the function of ILF3in the estrogen signaling pathways, we use the estradiol to induceMCF7, which could reveal the relationship between ILF3and estrogen. Further study theregulation mechanism of ILF3in regulating the expression of ER beta, we constructed the celllines of over-expression or RNAi knock-down ILF3. We could detect the change of ILF3bywestern blot after knocking down the ILF3, and could also detect the cell vitality effect byMTT assay. We found that estrogen can induce ILF3expression. When the ILF3was overexpressed, ER beta expression was up-regulated. After knock down the ILF3, ER betaexpression was inhibited. In the protein level, ILF3has a positive control ER beta. MTTResults showed that down-regulated ILF3didn’t affect the MCF7cell growth rate apparently.For further studying the relationship between ILF3and ER beta, we constructed the celllines of RNAi knock-down ER beta. The result showed that down-regulation of ER beta couldinhibit ILF3expression. All the results provided new clues on the further research for ILF3function and the theory basis for regulation mechanisms of ER beta, which provides anexperimental evidence for estrogen signaling pathways.