Two small RNAs encoded within the first 1.5 kilobases of the herpes simplex virus type 1 latency-associated transcript can inhibit productive infection and cooperate to inhibit apoptosis.
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is abundantly expressed in latently infected trigeminal ganglionic sensory neurons. Expression of the first 1.5 kb of LAT coding sequences is sufficient for the wild-type reactivation phenotype in small animal models of infection. The ability of the first 1.5 kb of LAT coding sequences to inhibit apoptosis is important for the latency-reactivation cycle. Several studies have also concluded that LAT inhibits productive infection. To date, a functional LAT protein has not been identified, suggesting that LAT is a regulatory RNA. Two small RNAs (sRNAs) were previously identified within the first 1.5 kb of LAT coding sequences. In this study, we demonstrated that both LAT sRNAs were expressed in the trigeminal ganglia of mice latently infected with an HSV-1 strain that expresses LAT but not when mice were infected with a LAT null mutant. LAT sRNA1 and sRNA2 cooperated to inhibit cold shock-induced apoptosis in mouse neuroblastoma cells. LAT sRNA1, but not LAT sRNA2, inhibited apoptosis less efficiently than both sRNAs. When rabbit skin cells were cotransfected with plasmids that express LAT sRNA1 and HSV-1 genomic DNA, the amount of infectious virus released was reduced approximately 3 logs. Although LAT sRNA2 was less effective at inhibiting virus production, it inhibited expression of infected cell protein 4 (ICP4). Neither LAT sRNA had an obvious effect on ICP0 expression. These studies suggested that expression of two LAT sRNAs plays a role in the latency-reactivation cycle by inhibiting apoptosis and productive infection.
Shen
Wenwen
W
Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska 685031, USA.
Sa e Silva
Mariana
M
Jaber
Tareq
T
Vitvitskaia
Olga
O
Li
Sumin
S
Henderson
Gail
G
Jones
Clinton
C
D000818:Animals; D017209:Apoptosis; D006561:Herpes Simplex / Q000821:virology; D051379:Mice; D035683:MicroRNAs / Q000235:genetics*; D009447:Neuroblastoma / Q000473:pathology / Q000821:virology; D012367:RNA, Viral / Q000502:physiology*; D011817:Rabbits; D011984:Sensory Receptor Cells / Q000821:virology*; D012668:Trigeminal Ganglion / Q000821:virology; D014775:Virus Activation / Q000235:genetics; D017735:Virus Latency / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics
D035683:MicroRNAs; D012367:RNA, Viral; C477253:latency associated transcript, herpes simplex virus-1