biostudies-literatureDwyer KWayne State UniversityNational Institute of General Medical Sciencese1012051https://www.ebi.ac.uk/biostudies/studies/S-EPMC12935305biostudies-literatureUnknown22(2)The process of transcription and cotranscriptional mRNA processing are facilitated by myriads of molecular interactions. To elucidate the protein-protein interactions that occur during transcription cycle of RNAPII, we performed mass spectrometry of affinity purified termination complexes from chromatin fraction. Quantitative proteomic analysis revealed interaction of termination factors with TFIIB, TFIID and SAGA complex. Furthermore, all three termination complexes displayed statistically significant interactions with Prp19, Prp43, Sub2, Snu114, Brr2 and Smb1 splicing factors. Since Prp19 consistently emerged as the interactor of both initiation and termination complexes, we affinity-purified the factor and performed mass spectrometry. Prp19 exhibited interactions with subunits of TFIID,PLoS geneticsProtein-interaction network analysis reveals the role of Prp19 splicing factor in transcription of both intron-containing and intron-lacking genes.PMC129353051R01GM146803-05Grant #T32GM142519UROP undergraduate research fellowshipRumble fellowshipDhoondia ZAnsari AAwada AEssak MADwyer KfalseProtein-interaction network analysis reveals the role of Prp19 splicing factor in transcription of both intron-containing and intron-lacking genes.The process of transcription and cotranscriptional mRNA processing are facilitated by myriads of molecular interactions. To elucidate the protein-protein interactions that occur during transcription cycle of RNAPII, we performed mass spectrometry of affinity purified termination complexes from chromatin fraction. Quantitative proteomic analysis revealed interaction of termination factors with TFIIB, TFIID and SAGA complex. Furthermore, all three termination complexes displayed statistically significant interactions with Prp19, Prp43, Sub2, Snu114, Brr2 and Smb1 splicing factors. Since Prp19 consistently emerged as the interactor of both initiation and termination complexes, we affinity-purified the factor and performed mass spectrometry. Prp19 exhibited interactions with subunits of TFIID,2026-01-01T00:00:00Z2026 Feb2026-07-16T21:38:28.636Z2026-07-10T03:16:26.795ZS-EPMC129353054171934810.1371/journal.pgen.1012051