A Structural Basis for BRD2/4-Mediated Host Chromatin Interaction and Oligomer Assembly of Kaposi Sarcoma-Associated Herpesvirus and Murine Gammaherpesvirus LANA Proteins
Figure 2
Oligomerization of the KSHV and MHV-68 LANA CTDs.
A: Oligomeric assemblies of kLANA (top) and mLANA (below) CTD dimers as found in the respective crystals. Inter-chain contact areas within and between dimers are indicated. B: Details on the oligomerization sites of kLANA (left) and mLANA CTDs (right), viewed from the center of the ring (kLANA, monoclinic crystal) and the top of the linear chain (mLANA). Color scheme corresponds to Figure 1A. C: Flow profiles (black graph) and molecular weight (red graph) of kLANA(1013-1149) (top) and mLANA(124-260) (bottom) in asymmetric field flow fractionation. D: Oligomerization assay with kLANA mutants. Top left: Western blot detecting FL kLANA wt or mutants bound to GST-fused kLANA wt or mutant CTDs. Bottom left: Ponceau S –stained WB membrane showing GST-LANA(934–1162) used in this assay. (e.v.) empty vector, (-) GST only, (MUT) mutant GST-LANA CTD always corresponding to the FL LANA mutant indicated above. Right: Expression of FL LANA proteins in eukaryotic cells. The aberrant running behavior of some mutants might be due to different posttranslational modification. E: EMSA with LBS1+2 oligonucleotide and GST-LANA(934-1162) oligomerization deficient mutants. (wt+comp.) control with 10× excess of unlabeled probe. Right: Expression of GST-LANA CTD proteins; Coomassie stained SDS PAGE gel. F: Transient replication assay with oligomerization mutants and pGTR4 vector in HeLa cells. Panel I: Southern blot of replicated DNA, remaining after digest with MfeI and DpnI. Panel II: Southern blot of input DNA linearized with MfeI; pEGFP does not replicate and serves as an internal control. Assay was performed in duplicates. Panel III: LANA expression. Panel IV: Actin loading control. (-) empty vector control.