Irell and Manella Graduate School of Biological Sciences 1 article published in JoVE Immunology and Infection Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry Jerlisa Ann C. Arizala1,2, Pritsana Chomchan1, Haitang Li1, Roger Moore3, Helen Ge3, Dominique L. Ouellet1, John J. Rossi1,2 1Molecular and Cellular Biology Department, Beckman Research Institute at the City of Hope, 2Irell & Manella Graduate School of Biological Sciences, 3Department of Molecular Immunology, Beckman Research Institute and the City of Hope Here we describe Rev immunoprecipitation in the presence of HIV-1 replication for mass spectrometry. The methods described can be used for the identification of nucleolar factors involved in the HIV-1 infectious cycle and are applicable to other disease models for the characterization of understudied pathways.