A herpes simplex virus type 1 mutant expressing a baculovirus inhibitor of apoptosis gene in place of latency-associated transcript has a wild-type reactivation phenotype in the mouse.
The latency-associated transcript (LAT) is essential for the wild-type herpes simplex virus type 1 (HSV-1) high-reactivation phenotype since LAT- mutants have a low-reactivation phenotype. We previously reported that LAT can decrease apoptosis and proposed that this activity is involved in LAT's ability to enhance the HSV-1 reactivation phenotype. The first 20% of the primary 8.3-kb LAT transcript is sufficient for enhancing the reactivation phenotype and for decreasing apoptosis, supporting this proposal. For this study, we constructed an HSV-1 LAT- mutant that expresses the baculovirus antiapoptosis gene product cpIAP under control of the LAT promoter and in place of the LAT region mentioned above. Mice were ocularly infected with this mutant, designated dLAT-cpIAP, and the reactivation phenotype was determined using the trigeminal ganglion explant model. dLAT-cpIAP had a reactivation phenotype similar to that of wild-type virus and significantly higher than that of (i) the LAT- mutant dLAT2903; (ii) dLAT1.5, a control virus containing the same LAT deletion as dLAT-cpIAP, but with no insertion of foreign DNA, thereby controlling for potential readthrough transcription past the cpIAP insert; and (iii) dLAT-EGFP, a control virus identical to dLAT-cpIAP except that it contained the enhanced green fluorescent protein open reading frame (ORF) in place of the cpIAP ORF, thereby controlling for expression of a random foreign gene instead of the cpIAP gene. These results show that an antiapoptosis gene with no sequence similarity to LAT can efficiently substitute for the LAT function involved in enhancing the in vitro-induced HSV-1 reactivation phenotype in the mouse.
Jin
Ling
L
Department of Ophthalmology, University of California, Irvine, School of Medicine, 92697, USA.
Perng
Guey-Chuen
GC
Mott
Kevin R
KR
Osorio
Nelson
N
Naito
Julia
J
Brick
David J
DJ
Carpenter
Dale
D
Jones
Clinton
C
Wechsler
Steven L
SL
D000818:Animals; D017209:Apoptosis; D016367:Baculoviridae / Q000235:genetics*; D002460:Cell Line; D005260:Female; D017353:Gene Deletion; D006561:Herpes Simplex / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000235:genetics* / Q000502:physiology*; D051034:Inhibitor of Apoptosis Proteins; D051379:Mice; D035683:MicroRNAs; D010641:Phenotype; D011506:Proteins / Q000235:genetics* / Q000502:physiology; D011817:Rabbits; D011995:Recombination, Genetic; D012668:Trigeminal Ganglion / Q000821:virology; D014764:Viral Proteins / Q000235:genetics* / Q000502:physiology; D014775:Virus Activation; D014779:Virus Replication
D051034:Inhibitor of Apoptosis Proteins; D035683:MicroRNAs; D011506:Proteins; D014764:Viral Proteins; C477253:latency associated transcript, herpes simplex virus-1