Kazrin Is A New Poly A RNA Binding Protein And May Involve In MRNA Intracellular Transport And Localization

Object:mRNA intracellular transport and localization are very important in post-transcriptional regulation of gene expression. Molecular motors power ribonucleotide protein (RNP) cargoes moving along the cytoskeleton, but how they interact is still unclear. We have found that Kazrin can interact with the kinesin light chain(KLC) and bind mRNA, but we do not know the specific binding sequence. Our research is to find out the specific binding sequence of Kazrin and explore the role may play in mRNA intracellular transport and localization.Methods:GST-Kazrin was expressed and reacted with the total mRNA from mouse brain and embryo. Extracted the target then used RT-PCR with the random6-8primers. TA cloned and selected the positive vectors, then sended to sequence. Northern-western Blot and UV-Crosslinked Co-IP were employed to test the binding sequence in vitro and in vivo respectly. Immuno-fluorescence (IF) and in situ hybridization were taken to show the co-localization of Kazrin in fixed U373cells.Results:Poly A tail of the mRNA is the specific binding sequence of Kazrin. We have found that there were no Poly A, there would be no binding in vivo and in vitro. Besides, We could find that Kazrin colocalized with Kinesin, Microtubulins in the U373cells. From structure to function, we suspect that Kazrin would involve in mRNA intracellular transport and localization.Conclusion:Many excellent studies focus on mRNA transport have been conducted to discover the mechanisms by which motor proteins transport mRNAs around the cell. It is still an enigma how the most localized transcripts are assembled with the motor proteins. Here we provide a potential answer. Kazrin can associate with the KLC, recognizing the polyA tail and binding it. Kazrin colocalized with Kinesin, Microtubulins and Poly A RNA in the U373cells gave clues that Kazrin would involve in mRNA intracellular transport and localization. These characters make kazrin a reasonable candidate of linkers connecting the mRNPs cargoes and kinesin.