Abstract
We have previously shown that clusters of guanine quadruplex (G4) structures can form in the human herpes simplex-1 (HSV-1) genome. Here we used immunofluorescence and immune-electron microscopy with a G4-specific monoclonal antibody to visualize G4 structures in HSV-1 infected cells. We found that G4 formation and localization within the cells was virus cycle dependent: viral G4s peaked at the time of viral DNA replication in the cell nucleus, moved to the nuclear membrane at the time of virus nuclear egress and were later found in HSV-1 immature virions released from the cell nucleus. Colocalization of G4s with ICP8, a viral DNA processing protein, was observed in viral replication compartments. G4s were lost upon treatment with DNAse and inhibitors of HSV-1 DNA replication. The notable increase in G4s upon HSV-1 infection suggests a key role of these structures in the HSV-1 biology and indicates new targets to control both the lytic and latent infection.
Highlights
Guanine-rich DNA sequences can form stable fourstranded guanine quadruplex (G4) structures based on the formation of G-quartets, which are stabilized by Hoogsteen-type hydrogen bonds between guanines and monovalent cations between the G-quartets [1].In eukaryotes, G4s have been shown to occur in functionally important regions of the genome: in telomeres, G-rich micro- and mini-satellites, within promoters, and in ribosomal DNA repeat arrays [2,3,4]
We have previously shown that at least four G-rich repeated sequences in the herpes simplex-1 (HSV-1) genome can fold into G4 structures in vitro [17]
Since the anti-G4 1H6 antibody (Ab) has been reported to have broad specificity for many but not all G4 structures [8], we initially tested its affinity for the selected herpes simplex virus-1 (HSV1) G4-forming sequences in vitro by Surface plasmon resonance (SPR)
Summary
G4s have been shown to occur in functionally important regions of the genome: in telomeres, G-rich micro- and mini-satellites, within promoters, and in ribosomal DNA (rDNA) repeat arrays [2,3,4]. Human DNA G4 motifs have been reported to be associated with recombination prone regions [5] and to show mutational patterns that preserved the potential to form G4 structures [4,6]. The presence of functionally significant G4 DNA motifs in the human immunodeficiency virus (HIV) has been reported by us and others both in the promoter [12,13,14] and Nef coding regions [15]. Multiple conserved and extended clusters of G4 forming sequences were observed, covering about 2,000 bp of the 152,000 bp-viral genome
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
