Status of the transcription factors database (TFD)

Powell

The Journal of Immunology

et al. 2000

232

175

IL-10 is an 18-kDa cytokine with a key role in homeostatic control of inflammatory and immune responses. We have investigated how transcription of the IL-10 gene is regulated, so as to be able to understand the circumstances of IL-10 expression in both health and disease. In the mouse, IL-10 gene expression is regulated by a TATA-type promoter with a critical cis-acting element containing GGA repeats located at −89 to −77. Its complementary sequence is similar to the cis-acting elements (TCC repeats) in the promoters of genes encoding epidermal growth factor receptor and CD58. All these elements comprise a common CCTCCT sequence with less conserved C + T-rich sequences. Eliminating this CCTCCT sequence results in a marked reduction in promoter activity, suggesting a necessary role in IL-10 gene expression. Despite its dissimilarity to the G + C-rich Sp1 consensus sequence (GC box), Sp1 and Sp3 transcription factors could be shown to bind to this motif. The requirement for Sp1 and Sp3 in transcription of IL-10 was confirmed using Drosophila SL2 cells, which lack endogenous Sp factors. These results suggest that the transcription of IL-10 is positively regulated by both Sp1 and Sp3.

Section: Il-10 Gene Expression Is Regulated By a Cctcct Motifmentioning

confidence: 99%

IL-10 Gene Expression Is Controlled by the Transcription Factors Sp1 and Sp3

Powell

The Journal of Immunology

et al. 2000

232

175

Journal of Biological Chemistry

“…The second protected region extends from Ϫ46 to Ϫ70 and includes a significant homology to an AP1 recognition site. Footprint III shows no sequence similarity to any of the known protein-binding sites, as revealed by a search in transcription factor site data bases (42,43). The region between Ϫ150 and Ϫ96 (footprints IV and V) adjoins sequences bearing some resemblance to several putative transcription factor binding sites, including cAMP response element, AP1, and AP4.…”

Section: Molecular Cloning Of the 5ј-flanking Region Of Rat Livermentioning

confidence: 99%

Characterization of Rat Liver-specific Methionine Adenosyltransferase Gene Promoter

Álvarez

Sánchez-Góngora²,

Mingorance

et al. 1997

Methionine adenosyltransferase is a ubiquitous enzyme that catalyzes the only known route of biosynthesis of S-adenosylmethionine, the major methyl group donor in cell metabolism. In mammals, two different methionine adenosyltransferases exist: one is confined to the liver, and the other one is distributed in extrahepatic tissues. In the present study, we report the cloning of the 5 -flanking region of liver-specific methionine adenosyltransferase gene from rat. Two closely spaced sites for transcriptional initiation were identified by primer extension analysis. The major transcription start site was determined to be 29 nucleotides downstream from the putative TATA box. Transient transfection assays of constructs containing sequentially deleted 5 -flanking sequences fused to the luciferase gene showed that rat hepatic methionine adenosyltransferase promoter was able to efficiently drive reporter expression not only in liver-type cells (rat hepatoma H35 cells and human hepatoblastoma HepG2 cells) but also in Chinese hamster ovary cells. Two regions spanning nucleotides ؊1251 to ؊958 and ؊197 to ؉65 were found to be crucial for the promoter efficiency. The distal upstream region contains elements that positively regulate promoter activity in H35 and HepG2 cells but are ineffective in Chinese hamster ovary cells. Eight protein binding sites were characterized in both regions by DNase I footprinting analysis. Two of these elements, sites A and B, located in the distal region, were found to be essential for the regulation of promoter activity. Electrophoretic mobility shift assays and competition experiments showed that site A is recognized by an NF1 protein. Site B was able to interact with a member of HNF-3 family when nuclear extracts from rat liver and H35 cells were used in the in vitro assay, but an additional binding activity to an NHF1-like protein was obtained with the hepatoma cell extracts. It is suggested that this differential binding can contribute to the cell specificity of promoter function.

Molecular and Cellular Biology

“…The list includes several proto-oncogenes and cytokine genes. Subsequently, we examined whether the Gfi-1 binding site is consistently near or overlaps with the binding site(s) of another factor(s) (Transcription Factors Database [15]). Such an association could be interpreted to suggest that Gfi-1 binds DNA in concert with another factor(s).…”

Section: Vol 16 1996mentioning

confidence: 99%

Gfi-1 Encodes a Nuclear Zinc Finger Protein That Binds DNA and Functions as a Transcriptional Repressor

Zweidler‐McKay

Grimes

Flubacher

et al. 1996

277

285

The Gfi-1 proto-oncogene encodes a zinc finger protein with six C 2 H 2 -type, C-terminal zinc finger motifs and is activated by provirus integration in T-cell lymphoma lines selected for interleukin-2 independence in culture and in primary retrovirus-induced thymomas. Gfi-1 expression in adult animals is restricted to the thymus, spleen, and testis and is enhanced in mitogen-stimulated splenocytes. In this report, we show that Gfi-1 is a 55-kDa nuclear protein that binds DNA in a sequence-specific manner. The Gfi-1 binding site, TAAATCAC(A/ T)GCA, was defined via random oligonucleotide selection utilizing a bacterially expressed glutathione S-transferase-Gfi-1 fusion protein. Binding to this site was confirmed by electrophoretic mobility shift assays and DNase I footprinting. Methylation interference analysis and electrophoretic mobility shift assays with mutant oligonucleotides defined the relative importance of specific bases at the consensus binding site. Deletion of individual zinc fingers demonstrated that only zinc fingers 3, 4, and 5 are required for sequence-specific DNA binding. Potential Gfi-1 binding sites were detected in a large number of eukaryotic promoter-enhancers, including the enhancers of several proto-oncogenes and cytokine genes and the enhancer of the human cytomegalovirus (HCMV) major immediate-early promoter, which contains two such sites. HCMV major immediate-early-chloramphenicol acetyltransferase reporter constructs, transfected into NIH 3T3 fibroblasts, were repressed by Gfi-1, and the repression was abrogated by mutation of critical residues in the two Gfi-1 binding sites. These results suggest that Gfi-1 may play a role in HCMV biology and may contribute to oncogenesis and T-cell activation by repressing the expression of genes that inhibit these processes.