IDENTIFICATION OF A 2ND ATF CREB-LIKE ELEMENT IN THE HERPES-SIMPLEX VIRUS TYPE-1 (HSV-1) LATENCY-ASSOCIATED TRANSCRIPT (LAT) PROMOTER/

The herpes simplex virus type-1 (HSV-1) latency-associated transcript (LAT) promoter (LP) has been shown to function in a cell type-specific manner. We have constructed an extensive series of PCR deletion mutat ions of the LP from nucleotides +1 to -348 to delineate the specific s equences involved in the cell type-specific activity of the HSV-1 LP. This series of 5' LP deletion constructs has been transiently transfec ted into both C1300 (neuronal) and L929 (nonneuronal) cells. When nucl eotides -75 to -83 were added to nucleotides +1 to -74, a three- to fo urfold C1300-specific increase in promoter activity was observed. In a ddition, when sequences upstream of nucleotide -211 were added to nucl eotides +1 to -211, a second threefold increase in promoter activity w as observed in C1300 cells. To begin to understand the biochemical bas is for these observations, we have examined the interaction of a segme nt of the HSV-I LP (nucleotides -54 to -134) with factors present in n euronal and nonneuronal nuclear extracts. This region of the LP contai ns the sequence most proximal to the transcriptional start site demons trated to be involved in cell type-specificity (nucleotides -75 to -83 ). By coupling the functional studies with electrophoretic mobility sh ift (EMS), oligonucleotide competition EMS, and antibody supershift EM S analyses, we have demonstrated that members of the activating transc ription factor (ATF)/cyclic-AMP response element binding protein (CREB ) transcription factor family interact with nucleotides -75 to -83 of the HSV-I LP. The identification of a novel ATF/CREB-like element in t he HSV-1 LP may facilitate the understanding of neuronal factors which regulate LAT expression during HSV-1 infection. These studies may ult imately provide additional insight concerning the role of HSV-1 LAT in the regulation of viral latency and reactivation. (C) 1994 Academic P ress, Inc.