In this project, we identified a novel RNA-binding protein, MHZ9. And we analyzed the potential proteins interacted with MHZ9 through immunoprecipitation-mass spectrometry (IP-MS). The N-terminal domain of MHZ9 (MHZ9-N) contains a putative RNA splicing and modification domain PRP4. To identify RNA binding sites in the MHZ9-N. We performed XRNAX-IP-MS assay.