The latency-associated transcript promoter of pseudorabies virus directs neuron-specific expression in trigeminal...

The latency-associated transcript (LAT) promoter of pseudorabies virus (PRV) is unique among viral promoters in that it remains active in trigeminal ganglia during the latent state. It is not known which the viral or host proteins regulate expression of the PRV LAT gene in latently infected neurons. To determine whether host transcriptional proteins in neurons can regulate the PRV LAT promoter in vivo, three transgenic mouse lines containing the PRV LAT promoter (LAP; LAP1 and LAP2) linked to the chloramphenicol acetyltransferase (CAT) gene were generated. All of the transgenic mouse lines, in the absence of the viral proteins, displayed strong expression of the transgene in trigeminal ganglia in addition to other neuronal tissues such as cerebral cortex, cerebellum, hippocampus and olfactory bulb. Expression of the transgene in neurons of trigeminal ganglia was demonstrated by in situ hybridization. These data provide direct evidence that neuronal transcription factors are sufficient to activate the PRV LAP in vivo and that the promoter is neuron-specific.