Human Cytomegalovirus (HCMV) Immediate early proteins, gene expression and signaling

Transcription

1 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 X zhuhu@umdnj.edu QuickTime and a decompressor are needed to see this picture. Electron Cryomicroscopy and 3D Reconstruction From Dr. H. Zhou

2 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

3 Virus Herpesvirus, dsdna virus ~80% of adults are infected Transmission in utero and at any age - body fluids breast feeding, blood transfusion

4 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

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6 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 reactivation +/- Primary /+ Reactivation /- Primary, not from graft 10 10

7 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

8 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

9 Prevention and treatment Vaccines: AD169, Towne - not effective Antivirals: Ganciclovir - effective

10 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

11 Acyclovir OH Ganciclovir Viral kinase Acyclovir monophosphate Cellular l kinase Acyclovir triphosphate Viral DNA polymerase Chain termination

12 HCMV Virion Structure icosahedral nucleocapsid dsdna genome envelop etegument glycoprotein H. Zhu

13 HCMV Genomic Structure CMV (230kb) UL US AD169 Towne Toledo PH TR FIX kb

14 HCMV Encodes Potential ORFs Murphy et al, 2003

15 Early Events of HCMV Infection HCMV gh gb gm/n HSPG EGFR? Integrins gm/n gh IE

16 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)

17 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)

18 Is IE2 essential for HCMV replication?

19 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

20 Generation of Recombinant HCMV kan R Flanking seqs. (40 bp) E. coli DY 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

21 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

22 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 /

23 Do IE1 and IE2 directly regulate viral gene expression? IE1 IE2??? IE E L E

24 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

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26 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

27 Control (9-mer)

28 Anti-HSV gb Anti-HCMV IE1/2 Merge

29 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

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31 What Are the Host Response to HCMV? HCMV gm/n gb gh HSPG HCMVR IE?

32 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

33 ISRE GAS

34 What is required for induction of ISGs? HCMV HSPG gm/n gb gh HCMVR? IE ISG

35 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 -

36 No growth: 45; Severe growth: 12; Moderate growth defect: 23; Growth like WT: 68; Enhanced growth: 4 Dunn et al., 2003, PNAS

37 Tissue Tropism A: Fibroblast cells; B. Epithelial cells; C. Endothelial cells

38 CMV (240kb) UL US AD169 Towne Toledo PH TR FIX kb

39 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

40 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

41 Construction of A HCMV with a Luciferase Gene Luciferase (UL62/UL63) Toledo Luciferase HCMV BAC HCMV luc

42 Bioluminescence Imaging Technique (Xenogen IVIS Imaging System) A. Virus w/ Luc. B. Animal/cell models C. Image acquisition D. Data analysis Toledo Toledo Luc

43 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

44 UL US AD169 Towne Toledo PH TR FIX kb UL138 UL133 UL135 UL136 UL139 UL141 UL142 UL143 UL145 UL147 UL148 UL132 UL130 UL149 UL140 UL144 UL146 UL134 UL137 UL150 UL151