Browsing by Author "Kerschner, Jenny L."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Casein Kinase II Phosphorylation of Spt6 Enforces Transcriptional Fidelity by Maintaining Spn1-Spt6 Interaction
    (Elsevier, 2018-12-18) Dronamraju, Raghuvar; Kerschner, Jenny L.; Peck, Sarah A.; Hepperla, Austin J.; Adams, Alexander T.; Hughes, Katlyn D.; Aslam, Sadia; Yoblinski, Andrew R.; Davis, Ian J.; Mosley, Amber L.; Strahl, Brian D.; Biochemistry and Molecular Biology, School of Medicine
    Spt6 is a histone chaperone that associates with RNA polymerase II and deposits nucleosomes in the wake of transcription. Although Spt6 has an essential function in nucleosome deposition, it is not known whether this function is influenced by post-translational modification. Here, we report that casein kinase II (CKII) phosphorylation of Spt6 is required for nucleosome occupancy at the 5' ends of genes to prevent aberrant antisense transcription and enforce transcriptional directionality. Mechanistically, we show that CKII phosphorylation of Spt6 promotes the interaction of Spt6 with Spn1, a binding partner required for chromatin reassembly and full recruitment of Spt6 to genes. Our study defines a function for CKII phosphorylation in transcription and highlights the importance of post-translational modification in histone chaperone function.
  • Thumbnail Image
    Item
    Quantitative Analysis of Dynamic Protein Interactions during Transcription Reveals a Role for Casein Kinase II in Polymerase-associated Factor (PAF) Complex Phosphorylation and Regulation of Histone H2B Monoubiquitylation
    (American Society for Biochemistry and Molecular Biology, 2016-06-24) Bedard, Lynn Glowczewski; Dronamraju, Raghuvar; Kerschner, Jenny L.; Hunter, Gerald O.; Axley, Elizabeth DeVlieger; Boyd, Asha K.; Strahl, Brian D.; Mosley, Amber L.; Biochemistry and Molecular Biology, School of Medicine
    Using affinity purification MS approaches, we have identified a novel role for casein kinase II (CKII) in the modification of the polymerase associated factor complex (PAF-C). Our data indicate that the facilitates chromatin transcription complex (FACT) interacts with CKII and may facilitate PAF complex phosphorylation. Posttranslational modification analysis of affinity-isolated PAF-C shows extensive CKII phosphorylation of all five subunits of PAF-C, although CKII subunits were not detected as interacting partners. Consistent with this, recombinant CKII or FACT-associated CKII isolated from cells can phosphorylate PAF-C in vitro, whereas no intrinsic kinase activity was detected in PAF-C samples. Significantly, PAF-C purifications combined with stable isotope labeling in cells (SILAC) quantitation for PAF-C phosphorylation from wild-type and CKII temperature-sensitive strains (cka1Δ cka2–8) showed that PAF-C phosphorylation at consensus CKII sites is significantly reduced in cka1Δ cka2–8 strains. Consistent with a role of CKII in FACT and PAF-C function, we show that decreased CKII function in vivo results in decreased levels of histone H2B lysine 123 monoubiquitylation, a modification dependent on FACT and PAF-C. Taken together, our results define a coordinated role of CKII and FACT in the regulation of RNA polymerase II transcription through chromatin via phosphorylation of PAF-C.