Viruses, Cells and Disease November 13, 2008 Human Cytomegalovirus (HCMV) Immediate early proteins, gene expression and signaling Dr. Hua Zhu ICPH E350D UMDNJ - New Jersey Medical School 973-972-4483 X 2-6488 zhuhu@umdnj.edu QuickTime and a decompressor are needed to see this picture. Electron Cryomicroscopy and 3D Reconstruction From Dr. H. Zhou
Introduction 1. Medical aspects of HCMV 2. HCMV structure 3. HCMV replication Special topics 1. IE1 and IE2 functions 2. A HCMV-induced signal transduction pathway (discuss two papers next week) 3. Functional profiling of HCMV genome 4. Identification of HCMV pathogenic genes
Virus Herpesvirus, dsdna virus ~80% of adults are infected Transmission in utero and at any age - body fluids breast feeding, blood transfusion
Latency and Recurrence Latent in monocytes (Myeloid progenitor cells) Reactivates during pregnancy and in immunosuppressed states, resulting in cytomegalic inclusion disease (CID), CMV pneumonia, retinitis and hepatitis Pathogenicity In people with cancer, transplanted organs, AIDS or other immune deficiencies, CMV can cause severe diseases of the lung, liver, colon, eye or brain A leading cause of congenital birth defects HCMV infection in the lung Intranuclear inclusion with a clear zone
Transplant Recipients Immunosuppression Rates of CMV Infection and disease in liver transplant t patients according to types of infection Pretransplant serostatus of donor/recipient Type of infection Infection (%) Disease (%) +/+ Reinfection or 66 23 reactivation +/- Primary 77 61 -/+ Reactivation 49 10 -/- Primary, not from graft 10 10
HCMV and AIDS Common immediate cause of death in AIDS (25%) 70-90% show active CMV infection 30-40% develop CMV retinitis 95% homosexual men with AIDS have active HCMV infection CMV retinitis
Congenital HCMV Infection The most common virus globally to be transmitted in utero, affecting up to 2.5% of all live births (WHO) A leading cause of birth defects ~10% of infected fetuses exhibit damage of the CNSmental retardation hearing loss impaired vision
Prevention and treatment Vaccines: AD169, Towne - not effective Antivirals: Ganciclovir - effective
Anti-Herpesvirus Agents QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. Acyclovir (Zovirax - Glaxo) - for α herpesviruses Ganciclovir (Cytovene - Roche) - for β herpesviruses - Guanosine analogs Mechanism of Action: Specifically activated by virus-induced kinases, such as thymidine kinase of HSV and UL97 of CMV Terminate viral DNA chain elongation Selectively inactivate viral DNA polymerases and inhibit viral DNA elongation
Acyclovir OH Ganciclovir Viral kinase Acyclovir monophosphate Cellular l kinase Acyclovir triphosphate Viral DNA polymerase Chain termination
HCMV Virion Structure icosahedral nucleocapsid dsdna genome envelop etegument glycoprotein H. Zhu
HCMV Genomic Structure CMV (230kb) UL US AD169 Towne Toledo PH TR FIX 0 20 40 60 80 100 120 140 160 180 200 220 230 kb
HCMV Encodes 230-250 Potential ORFs Murphy et al, 2003
Early Events of HCMV Infection HCMV gh gb gm/n HSPG EGFR? Integrins gm/n gh IE
Overview of HCMV Gene Expression Patterns Cycloheximide IE? ctfs IE vtps X X X X X IE E E L E UL122 (IE2), UL123 (IE1), UL122 (IE2), UL123 (IE1), UL36, UL37, US3, UL119, TRS1 (IRS1)
HCMV Major IE Locus Major IE promoter TATA ATF/CREB AP1 SP1 NF-1 NF-κB E1 E2 E3 E4 E5 IE1 mrna IE1 protein (72 kd) IE2 mrna IE2 protein (86 kd)
Is IE2 essential for HCMV replication?
Construction of HCMV-BAC HCMV DNA BAC vector (GFP + Cm R ) Transfect HF cells Produce infectious HCMV Homology recombination Transfect HF cells Purify recombinant HCMV (Green) Infect new HF cells Isolate circular viral DNA Mutagenesis Specific Random Purify HCMV- BAC DNA HCMV-BAC Transform into E. coli Select Cm R colonies Screen full-length HCMV-BAC
Generation of Recombinant HCMV kan R Flanking seqs. (40 bp) E. coli DY380 32 C Degrades processively from the 5 ends of the break sites PCR kan R cassette Transform into DY380 ORF exo bet gam ci ORF kan R Incubate at 42 C Preparing electro- competent cells HCMV-BAC Defective λ prophage ts λ ci repressor Inhibits the recbcd exonuclease from attacking linear DNA Binds to the remaining 3 single strand tail,,protecting and preparing the recessed DNA for homologous strand invasion Select for kan R colonies at 32 C Confirm recombinant HCMV-BAC by PCR and Southern Transfect HF cells? Produce infectious HCMV..... kan R ΔORF mutant Isolate BAC DNA Dr. Neal Copeland
IE2 is essential for viral replication MIEP TATA E1 E2 E3 E4 E5 Deletion of exon 5 X WT IE2Δ IE2Δ WT anti-ie1 anti-ie2 Genotype Plaques WT 223 IE2Δ 0
IE2 is required for the early and late gene expression Immediate Early Early IE1 IE2 TRS1 TRL4 UL112 W Δ W Δ W Δ W Δ W Δ 1018 506/517 396 298 344 220
Do IE1 and IE2 directly regulate viral gene expression? IE1 IE2??? IE E L E
ChIP-Chip Chip Assay IE2 IE1? TFs Viral promoter Formaldehyde treat cells Isolate nuclei Sonicate Anti-HCMV IE1/2 or Anti-HSV gb Immunoprecipitate (anti-ie1/2) Reverse crosslinks Identify target DNA
ChIP-Chip Chip Assay 202 kb 204 kb 206 kb 208 kb 210 kb 212 kb 214 kb 216 kb 218 kb US12 US13 US14 US15 US16 US17 US18 US19 US20 US21 US22 US23 US24 US25 US26 US27 US28 PCR Input IP HCMV genomic chip Input + IP
Control (9-mer)
Anti-HSV gb Anti-HCMV IE1/2 Merge
IE1 IE2 IE E L E IE2 is essential for viral replication IE2 is required for viral early and late gene expression IE1 and IE2 directly regulate viral gene expression
What Are the Host Response to HCMV? HCMV gm/n gb gh HSPG HCMVR IE?
Identification of cellular genes altered after HCMV infection Differential display GeneChip (Affymetrix) cigs (IFN-stimulated genes, isgs) Activated by both live and killed HCMV Not require viral gene expression, viral DNA, and new protein synthesis Not mediated by IFNs or other cytokines HCMV directly activates ISGs cig1 cig6 cig24 cig2 5 cig3 4 cig41 cig4 2 cig43 cig49 cig52 cig5 3 contro l cig1 = isg54k
ISRE GAS
What is required for induction of ISGs? HCMV HSPG gm/n gb gh HCMVR? IE ISG
HCMV HSPG Is fusion required? gm/n gb gh PEG HCMVR HCMV: isg54k - cig49-7 SK - - W W M M - CFI: - + + - CFI HCMV: - - + + + PEG: - + - - + CFI: - - - + + isg54k - ISG? 7 SK -
No growth: 45; Severe growth: 12; Moderate growth defect: 23; Growth like WT: 68; Enhanced growth: 4 Dunn et al., 2003, PNAS
Tissue Tropism A: Fibroblast cells; B. Epithelial cells; C. Endothelial cells
CMV (240kb) UL US AD169 Towne Toledo PH TR FIX 0 20 40 60 80 100 120 140 160 180 200 220 230 kb
The Severe Combined Immunodeficient (SCID) Mice Model For Studying HCMV Pathogenesis thymus/liver tissue kidney kidney capsule 3 months Infected implants are harvested at different time and the amount of HCMV A thymus/liver implant is surgically is measured exposed and injected with HCMV
The clinical but not attenuated strains can replicate in the implanted human tissues Attenuated strains: AD169, Towne Clinical strains: Toledo Fibroblasts Yes Yes SCID-hu No Yes
Construction of A HCMV with a Luciferase Gene Luciferase (UL62/UL63) Toledo Luciferase 30000000 25000000 20000000 15000000 10000000 5000000 0 HCMV BAC HCMV luc
Bioluminescence Imaging Technique (Xenogen IVIS Imaging System) A. Virus w/ Luc. B. Animal/cell models C. Image acquisition D. Data analysis 1 2 3 4 5 6 7 8 Toledo Toledo Luc
Generation of Toledo-D and Toledo-R Mutants UL US AD169 Towne Toledo Toledo-D Toledo-R Cultured cells SCID-hu (Thy/Liv) AD169 Yes No Towne Yes No Toledo Yes Yes Toledo-D Yes No Toledo-R Yes Yes The 15-kb Segment Contains the Crucial Genes for HCMV Replication in vivo
UL US AD169 Towne Toledo PH TR FIX 0 20 40 60 80 100 120 140 160 180 200 220 230 kb UL138 UL133 UL135 UL136 UL139 UL141 UL142 UL143 UL145 UL147 UL148 UL132 UL130 UL149 UL140 UL144 UL146 UL134 UL137 UL150 UL151