Lori Frappier (University of Toronto, Canada)
“New Functions for EBV Proteins in Manipulating Cellular Processes Important for Cancer”
- EBV lytic infection and cancer
- EBV encodes ~ 80 proteins, ~70 of which are only expressed in lytic infection
- EBV induced cancers are considered to be latent infections but lytic infection is also important because:
- 1 High viral load due to lytic infection precedes the development of NPC and
- Transcriptome data of 8 EBV positive gastric cancer
- EBV manipulation of the DNA damage response
- Herpesvirus cell line are dsDNA genome that are sensed by the cell as dsDNA breaks
- Screening or EBV proteins that decrease 53BP1 Fock
- Identification 8 EBV viral proteins that inhibit DDR, including tegument BKFR4
- BKRF4 binds histones through its N-terminal region —> histone ubiquitous inhibited (interferes with the DSB signaling by blocking is tone degradation) —> happens in gastric cancer so that DNA damage is accumulated
- Screening EBV proteins for global effects on cellular SUMOylation
- LMP1 upregulates SUMOylation / ICP0 (STUbL)
- 4 EBV proteins consistently upregulated SUMOylation
- 1 EBV protein consistently downregulated. (2013 PlLos Pathog 2013; 9(8) e1003506
- SUMO up-regulator SM/EB2 known roles in mRNA export and splicing and an uncharacteristic tole in transcriptional activation of some EBV genes SM has homogeneous with similar roles in other herpesviruses (HSV ICP27, CMV UL69)
- Is SM a SUMO E3 ligament?
- EBV SM and CMV UL69 preferentially bind SUMO1
- HSV ICP27 preferentially binds SUMO2
- BORF2
- Large submit of the viral ribonucleoriude reductive
- Conserved in all herpesviruses but catalytically inactive in CMV
- HSV1 homologous has anassitional role in inhintoing apoptosis (by binding cascade 8)
- APOBEC3 proteins (Cytidine delaminates) =. A3B
- BORF2 is specific to bind A3B
- BORF2 relocalizes A3B out the nucleus
- A3B localized to replicating EBV DNA in the absence of BORF2
- CRISPER KO of BORF2
- A3B localized to replicating EBV DNA in the absence of BORF2
- BORF2 proteins EBV genomes rom A3B editing during lytic replication, maintains the EBV genome integrity and infectivity
- ( by using 3D PCR (differential DN deamination? )assay of BORF2-null AGS-EBV)
- Effect of BORF2 KO on EBV infectivity
- A3B is deleted in Ankara cell!! (Thus BORF KO or not does not make difference!)
- EBNA1/DNA crystal structure
- EBNA1 function – mitosis segregation of the EBV genomes, transcription activation , DNA replication, p53 regulation and disruption of hist PML
- Genome-wade screen approach fo rvirual replication