LAT expression during an acute HSV infection in the mouse

Previous studies using cell culture systems to evaluate LAT expression demo nstrated that the LAT promoter expresses at much higher levels in neuroblas toma cell lines than fibroblast lines. The high level of LAT expression in neuronal-derived cell lines correlates with the high level of LAT accumulat ion observed in sensory ganglia neurons during a latent infection. We have found that using LAT promoters to express reporter genes from recombinant v iruses in vivo produces high levels of LAT promoter activity in the epithel ium of the mouse foot. An analysis of LAT promoter activity during an acute infection in the mouse clearly demonstrates that in contrast to studies pe rformed with selected cell lines, the LAT promoter expresses similar levels of reporter gene product in peripheral cells and in neurons. In addition, the amount of reporter gene product is higher when the LAT promoter is loca ted within the R-L as compared to the U-L region, and when expression is ad justed for copy number of the reporter construct, expression is roughly the same. These results suggest the activity of the LAT promoter varies greatl y according to cell type and that high levels of expression is not limited solely to neurons, especially in the in vivo setting. (C) 1999 Academic Pre ss.