Identification of interacting proteins with U4 snRNA with and without USP39

RNA splicing and protein degradation systems allow the functional adaptation of the proteome in response to changing cellular contexts. However, the regulatory mechanisms connecting these processes remain poorly understood. Here, we show that impaired spliceosome assembly caused by USP39 deficiency leads to a pathogenic splicing profile characterized by the use of cryptic 5′ splice sites. We performed MS analysis to identify the main interactors of U4 snRNA with and without USP39