title: GAL4-VP16 is an unusually potent transcriptional activator.
abstract: Recent work has defined a class of transcriptional activators, members of which activate transcription in yeast, plant, insect and mammalian cells. These proteins contain two parts: one directs DNA binding and the other, called the activating region, presumably interacts with some component of the transcriptional machinery. Activating regions are typically acidic and require some poorly-understood aspect of structure, probably at least in part an alpha-helix. Here we describe a new member of this class, formed by fusing a DNA-binding fragment of the yeast activator GAL4 to a highly acidic portion of the herpes simplex virus protein VP16 (ref. 11; also called Vmw65). VP16 activates transcription of immediate early viral genes by using its amino-terminal sequences to attach to one or more host-encoded proteins that recognise DNA sequences in their promoters. We show that the hybrid protein (GAL4-VP16) activates transcription unusually efficiently in mammalian cells when bound close to, or at large distances from the gene. We suggest that the activating region of VP16 may be near-maximally potent and that it is not coincidental that such a strong activator is encoded by a virus.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004268:DNA-Binding Proteins; D005047:Etoposide / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D005047:Etoposide