Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P51532 (transcriptional activator)
 6,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The phage T4 gene 45 protein (gp45), Escherichia coli beta and the eukaryotic proliferating cell nuclear antigen (PCNA) function in replication as processivity factors of their corresponding DNA polymerases. The T4 gp45 also functions as the transcriptional activator that connects expression of viral late genes to DNA replication. DNA tracking is an essential component of the replication and transcription regulatory functions of T4 gp45. The ability of gp45, beta and PCNA to track along DNA has been analyzed by photocrosslinking. Each of these proteins must be loaded onto DNA by a species-specific assembly factor. For gp45 and beta, the density of traffic along DNA is determined by a dynamic balance between continuous protein loading and unloading, and is also dependent on interaction with the conjugate single-stranded DNA binding protein.
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PMID:Detecting the ability of viral, bacterial and eukaryotic replication proteins to track along DNA. 795 99

The wild-type p53 protein is a transcriptional activator implicated in the control of cellular growth-related gene expression. Here, using a number of different cell lines and transient-transfection-transcription assays, we demonstrate that at low levels, wild-type p53 transactivates the human proliferating cell nuclear antigen (PCNA) promoter. When expressed at a similar level, the tumor-derived p53 mutants did not transactivate the PCNA promoter. We identified a p53-binding site on the human PCNA promoter with which p53 interacts sequence specifically. When placed on a heterologous synthetic promoter, the binding site functions as a wild-type p53 response element in either orientation. Deletion of the p53-binding site renders the PCNA promoter p53 nonresponsive, showing that wild-type p53 transactivates the PCNA promoter by binding to the site. At a higher concentration, wild-type p53 inhibits the PCNA promoter but p53 mutants activate. Transactivation by p53 mutants does not require the p53-binding site. These observations suggest that moderate elevation of the cellular wild-type p53 level induces PCNA production to help in DNA repair.
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PMID:Wild-type human p53 transactivates the human proliferating cell nuclear antigen promoter. 852 44

The transcription factor E2F regulates the expression of genes involved in the progression of G1/S transition and DNA replication in mammalian cells. We cloned and characterized a cDNA (NtE2F) corresponding to a E2F homolog of tobacco (Nicotiana tabacum). The transcription of NtE2F was induced as cells progressed from G1 to the S phase and expressed much earlier than that of the proliferating cell nuclear antigen (PCNA) gene. We demonstrated that NtE2F can interact with the tobacco retinoblastoma (Rb)-related protein in a yeast two-hybrid assay. To further characterize NtE2F, the trans-activation activity of NtE2F was examined by using a transient assay in the tobacco Bright Yellow-2 (BY-2) cells with NtE2F fused to the DNA-binding domain of the veast transcriptional activator GAL4. NtE2F activated the transcription of the beta-glucuronidase (GUS) reporter gene driven by a cauliflower mosaic virus (CaMV) 35S core promoter containing the GAL4-binding sequence. This is the first report of the identification of a functionally equivalent E2F-like gene in plants.
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PMID:Isolation and characterization of the E2F-like gene in plants. 1057 Oct 72

The CCAAT enhancer-binding protein (C/EBP) beta gene can produce several N-terminally truncated isoforms. Liver-enriched activator protein (LAP) is a transcriptional activator in many systems, whereas liver-enriched inhibitory protein (LIP) is regarded as a functional LAP antagonist. In this study, we examined the impact of these two proteins on cell cycle progression in the regenerating liver. Adenoviral overexpression of LAP, in addition to its role as a transactivator of liver-specific genes, led to a delayed S-phase entry of hepatocytes after partial hepatectomy (PH) in vivo. This delay was accompanied by decreased expression of cyclin A and E as well as proliferating cell nuclear antigen and decreased cyclin-dependent kinase 2 activity at the G1/S boundary. This observation is not explained by increased p21(CIP1/Waf1) expression or lack of phosphorylation of external LAP, but LAP overexpression triggered a decreased C/EBP-alpha/C/EBP-alpha-30 ratio and a reduced basal c-jun level in the liver. In contrast, adenoviral overexpression of LIP resulted in a stronger and earlier induction of cyclin A and E after PH, but did not change the timing and extent of cyclin-dependent kinase 2 activity or the amount of hepatocytes that entered S phase in this model. In the LIP expressing group, both C/EBP-alpha isoforms and c-jun were more strongly induced after PH. In conclusion, the LAP/LIP ratio is an important modulator of cell cycle progression during liver regeneration. In the context of previous studies, our results demonstrate that LAP, through a dose-dependent effect, withholds a dual activating and inhibiting role on hepatocyte proliferation in vivo.
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PMID:C/EBP beta isoforms LIP and LAP modulate progression of the cell cycle in the regenerating mouse liver. 1536 40

Nutrient absorption mediated by nutrient transporters expressed in the intestinal epithelium supplies substrates to support intestinal processes, including epithelial cell proliferation. We evaluated the role of Caudal type homeobox 2 (CDX2), an intestine-specific transcription factor, in the proliferation of pig intestinal epithelial cells (IPEC-1) and searched for novel intestinal nutrient transporter genes activated by CDX2. Our cloned pig CDX2 cDNA contains a "homeobox" DNA binding motif, suggesting it is a transcriptional activator. CDX2 overexpression in IPEC-1 cells increased cell proliferation, the percentage of cells in S/G2 phase, and the abundance of transcripts of the cell cycle-related genes Cyclin A2; Cyclin B; Cyclin D2; proliferating cell nuclear antigen; and cell cycle cyclin-dependent kinases 1, 2 and 4, as well as the predicted CDX2 target genes SLC1A1, SLC5A1 and SLC7A7. In addition, luciferase reporter and chromatin immunoprecipitation assays revealed that CDX2 binds directly to the SLC7A7 promoter. This is the first report of CDX2 function in pig intestinal epithelial cells and identifies SLC7A7 as a novel CDX2 target gene. Our findings show that nutrient transporters are activated during CDX2-induced proliferation of normal intestinal epithelial cells.
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PMID:CDX2 increases SLC7A7 expression and proliferation of pig intestinal epithelial cells. 2712 15