Comparing regions of the Epstein-Barr virus ZEBRA protein which function as transcriptional activating sequences in Saccharomyces cerevisiae and in B cells.
The ZEBRA protein activates expression of Epstein-Barr virus early-lytic-cycle genes in human B lymphocytes. Here it is shown that ZEBRA also behaves as a sequence-specific transcriptional activator in Saccharomyces cerevisiae. Deletional mutagenesis defined three regions of ZEBRA that participate in activation in S. cerevisiae. These regions are designated YI (amino acids [aa] 1 to 25), YII (aa 51 to 102), and YIII (aa 228 to 245). Two of the three regions of the native ZEBRA protein act together to mediate activation when assayed on ZEBRA binding sites. However, when fused to the DNA binding domain of GAL4 and assayed on GAL4 binding sites, regions YII and YIII were each sufficient to confer activation in S. cerevisiae. Regions of ZEBRA which affected activation in S. cerevisiae were also required in human B lymphocytes. The amino-terminal region of ZEBRA (aa 1 to 98) was required for activation both in S. cerevisiae and in human B cells; deletion of the carboxy-terminal 18 aa also significantly reduced activation in both cell types. Thus, the behavior of ZEBRA in human B cells and S. cerevisiae suggests that the protein contains universal activation motifs that interact with conserved components of the transcription machinery. However, certain deletion mutants of ZEBRA containing mutations in the N-terminal region exhibited discordant behaviors in S. cerevisiae and in B cells. For example, deletion of ZEBRA aa 26 to 51 impaired activation to a great extent in B cells but had little or no effect in S. cerevisiae. The discordant mutants may reflect interactions with a variable domain of a conserved component or unique interactions with specialized components of the basal transcription apparatus in different cells.
Miller
G
G
Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510-8064.
Himmelfarb
H
H
Heston
L
L
Countryman
J
J
Gradoville
L
L
Baumann
R
R
Chi
T
T
Carey
M
M
D001402:B-Lymphocytes; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics*; D005656:Fungal Proteins; D005786:Gene Expression Regulation; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D013045:Species Specificity; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors; D014158:Transcription, Genetic; D014764:Viral Proteins
C063676:BZLF1 protein, Herpesvirus 4, Human; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014764:Viral Proteins