Herpes simplex virus type 1. Speaker: Shao-Yu Tsai Adviser: Li-Kwan Chang Ph. D. Group I (dsdna) Subfamily: Alphaherpesvirinae

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A Mutation in the Human Herpes Simplex Virus Type 1 UL52 Zinc Finger Motif

Support Viral Replication Efficiently Yan Chen, Christine M.

Weller JOURNAL OF VIROLOGY, Aug. 2007, p.

D Herpes simplex virus type 1 Group: Family: Group I (ds) Herpesviridae

1 A Mutation in the Human Herpes Simplex Virus Type 1 UL52 Zinc Finger Motif Results in Defective Primase Activity but Can Recruit Viral Polymerase and Support Viral Replication Efficiently Yan Chen, Christine M. Livingston, Stacy D. Carrington-Lawrence, Ping Bai, and Sandra K. Weller JOURNAL OF VIROLOGY, Aug. 2007, p Speaker: Shao-Yu Tsai Adviser: Li-Kwan Chang Ph. D Herpes simplex virus type 1 Group: Family: Group I (ds) Herpesviridae Subfamily: Alphaherpesvirinae Genus: Simplexvirus Species: Herpes simplex virus 1 Prevalence: 70~90% among human Symptoms: cold sores, herpetic keratitis and encephalitis

2 Lantency nucleus Lytic cycle Ori Linear Ori stress Low Immunity Circular Ori replication Axon Ori Binding Protein

3 H/P complex Stimulate complex activity UL8 UL5 UL52 Contains 7 conserved helicase motifs Contains conserved primase motifs

4 Current anti-hsv treatments are mostly targeted to the viral polymerase. -Drug resistance UL52 Primase homologues

5 Result Construct a point mutation L986F(Leu Phe) Complement assay UL52 null virus infect cell Virus titer transfect Plasmids bearing UL52 gene Empty plasmid

6 Does UL52-L986F change any of the enzymatic activities of the complex? Expression and purification of H/P complex L986F enzymatic activities Primase 5 -to-3 helicase ssdependent NTPase binding Compare to WT

7 WT UL5 His-tagged WT UL8 WT UL52 or L986F cell Nickel Nickel column Elute out H/P complex Expression and purification of H/P complex L986F enzymatic activities Primase 5 -to-3 helicase ssdependent NTPase binding Compare to WT

8 Result Primase assay H/P complex + template + ATP UTP GTP- -- [α- 32 P]CTP 37 30min primer Incorporates [α- 32 P]CTP Without complex Expression and purification of H/P complex L986F enzymatic activities Primase 5 -to-3 helicase ssdependent NTPase binding Compare to WT

9 Result 32 P-labeled forked ( Without complex ) as substrate Result SSBP stimulates helicase activity 50 nm 0-60 min SSBP

10 Expression and purification of H/P complex L986F enzymatic activities Primase 5 -to-3 helicase ssdependent NTPase binding Compare to WT Result ATP hydrolysis is required for unwinding. The more ATP hydrolysis, the more Pi produced. Without ss

11 Expression and purification of H/P complex L986F enzymatic activities Primase 5 -to-3 helicase ssdependent NTPase binding Compare to WT Result Electrophoretic mobility shift assay (EMSA)

12 Expression and purification of H/P complex L986F enzymatic activities Primase 5 -to-3 helicase ssdependent NTPase binding Compare to WT ds UL5 H/P complex UL8 UL52 ss binding proteins RNA primer A functional UL52 is needed to recruit viral polymerase UL30 to the replication site. UL30 polymerase UL42 accessory protein

13 L986F is defect in primase activity, is it capable of recruiting UL30? Result Although lost its function, L986F can still support viral replication. Replication compartment JOURNAL OF VIROLOGY, Mar. 1997, p

protein-protein interaction Result Protein binds to proteins

14 L986F has a defect primase activity Low levels of primers is sufficient to recruit UL30 UL30 is recruited by protein-protein interaction Result Protein binds to proteins detergent extracted Protein binds to nucleic acid remained WT extracted

15 L986F has a defect primase activity Low levels of primers is sufficient to recruit UL30 UL30 is recruited by protein-protein interaction UL52 L986F shows a decrease in primase activity while an increase in helicase ssdependent NTPase and binding ability. The helicase/primase complex exhibits a complex pattern of interdependence. Viral polymerase may be recruited and tethered to the replication fork via protein-protein interaction.

16 31 binding. Protein-protein or protein-lipid interactions. Maintain zinc homeostasis. Protein structural integrity.

17 nickel-nta (nitrilotriacetic acid) conjugates

18 Immediate Early mrna Early Late

The 5 end problem. 3 5 Now what? RNA primers. DNA template. elongate. excise primers, elongate, ligate

The 5 end problem. 3 5 Now what? RNA primers. DNA template. elongate. excise primers, elongate, ligate 1 2 3 DNA Replication Viruses must replicate their genomes to make new progeny This always requires expression of at least one virus protein, sometimes many (hence always delayed after infection) DNA is