1: Biol Reprod. 2005 Sep;73(3):500-9. Epub 2005 May 11. A placenta-specific enhancer of the human syncytin gene. Cheng YH, Handwerger S. Department of Pediatrics, University of Cincinnati College of Medicine and Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA. The cis- and trans-acting factors that are critical for placenta-specific expression of the human syncytin gene are unknown. We identified a 146-base pair (bp) region of the 5'-flanking region of the human syncytin gene from nt-294 to -148 that is essential for basal gene expression in human BeWo and JEG3 choriocarcinoma cell lines but not in hepatoblastoma and kidney cell lines. Ligation of the 146-bp fragment to a SV40 promoter or a human beta-globin minimal promoter markedly enhanced promoter activity in the placenta cells but not in the liver and kidney cells. DNase I footprint assays indicated that nuclear extracts from BeWo cells but not HepG2 cells protected four regions (FP1-FP4) of the 146-bp fragment. Site-directed mutagenesis of an SP1-binding site in FP3 and a GATA-binding site in FP4 significantly repressed promoter activity in the placenta cells. Overexpression of SP1 (Sp1 transcription factor) and GATA2 (GATA binding protein 2) and GATA3 induced syncytin promoter activity but had little or no effect on the activities of syncytin promoter fragments containing mutations in the SP1- and GATA-binding sites. GATA2 and -3 mRNA levels increased markedly during spontaneous in vitro differentiation of human cytotrophoblast cells when the cytotrophoblast cells fused to form a syncytium. These findings strongly suggest that the 146-bp region of the 5'-flanking region (nt-294/-148) of the human syncytin gene acts as a placenta-specific enhancer. Binding of SP1 and GATA family members to this enhancer is critical for cell-specific expression of the syncytin gene. PMID: 15888734 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 2: J Cell Biochem. 2004 Dec 15;93(6):1178-87. Regulation of the GATA3 promoter by human T-cell lymphotropic virus type I Tax protein. Gilli SC, Salles TS, Saad ST. Hematology and Hemoterapy Center, State University of Campinas, Department of Clinical Medicine, Campinas, Sao Paulo, Brazil. The Human T-cell leukemia virus type I (HTLV-I) non-structural protein Tax plays a crucial role in cellular transformation. It activates the transcription factors of various cellular genes and interacts with cellular proteins. There is limited data available on the interaction between specific T-cell transcription factor GATA3 and Tax. Implications for the significance of GATA3 in T-cell development and function, T helper2 (Th2) differentiation, and a role of GATA3 during the immune response have been reported. To determine the effect of the Tax protein on GATA3 gene expression, we investigated the interaction between this protein and the GATA3 promoter and repressor regions. Results demonstrated an interaction between Tax and the GATA3 promoter via the transcription factor Sp1 and a role for Tax in the negative regulation of GATA3 expression, through its interaction with the repressor ZEB. This interaction may be involved in the pathophysiology of adult T-cell leukemia/lymphoma (ATL) and tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). Copyright 2004 Wiley-Liss, Inc. PMID: 15486968 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 3: Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2002 Apr;10(2):100-3. Sequence analysis of 5'-flanking region of human pax-5 gene exon 1B. Liu ML, Rahman M, Hirabayashi Y, Sasaki T. Department of Nephrology and Rheumatology, The Third Affiliated Hospital, Jiangxi Medical College, Nanchang 330008, China. Pax-5 gene is important transcription factor in B-lymphopoiesis and B-cell development. To understand the regulatory mechanism of pax-5 expression, the immediate 5'-flanking region (6 671 bp) of human pax-gene exon 1B was isolated and characterized. Analysis of the total sequence showed that the proximal promoter includes 3 CAT boxes, 1 SP1 and 1 E box. However, there was no consensus sequence for a TATA box in the 5'-flanking region. Putative regulatory sites of further upstream in the sequence revealed 6 LMO(2)COM, 5 NFAT, 2 LPOLYA-B, 3 GATA1, 2 AP4, 10 MZF1, 1 ETS1-B, 1 GATA3, 1 NKX25, 2 RORA1, 1 LYF1, 2 Ikaros2, 2 TCF11, 1 GATA-C and 1 FREAC7. Therefore, the 5'-flanking region of human pax-5 exon 1B could be involved in regulating the expression of human pax-5 and B-cell differentiation and development. PMID: 12513807 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 4: J Immunol. 1998 Aug 1;161(3):1399-405. A developmental stage-specific promoter directs germline transcription of D beta J beta gene segments in precursor T lymphocytes. Sikes ML, Gomez RJ, Song J, Oltz EM. Department of Microbiology and Immunology, Vanderbilt University Medical School, Nashville, TN 37232, USA. The tissue- and stage-specific assembly of Ag receptor genes is regulated by transcriptional control elements positioned within Ig and TCR loci. To further understand the role of cis-acting elements in these regulatory mechanisms, we have characterized a transcriptional promoter that drives germline expression of TCR beta gene segments in vivo. The activity of this promoter, termed PD beta, is restricted to a highly conserved 400-bp region located directly upstream from D beta 1-coding sequences. Maximal PD beta activity requires a TATA element situated within the D beta 1 recombination signal sequences and consensus binding sites for the ubiquitous SP1 and the T cell-specific GATA-3 transcription factors. When linked to active enhancer elements, PD beta directs transcription in most cell types; however, the TCR beta enhancer (E beta) stimulates PD beta function specifically in precursor T lymphocytes. These findings suggest that PD beta/E beta interactions may contribute to differential regulation of regions within the TCR beta locus during thymocyte development. PMID: 9686603 [PubMed - indexed for MEDLINE] --------------------------------------------------------------- 5: Endocrinology. 1997 Aug;138(8):3417-25. The proximal promoter region of the gene encoding human 17beta-hydroxysteroid dehydrogenase type 1 contains GATA, AP-2, and Sp1 response elements: analysis of promoter function in choriocarcinoma cells. Piao YS, Peltoketo H, Vihko P, Vihko R. Biocenter Oulu and Department of Clinical Chemistry, University of Oulu, Finland. The 5'-flanking region from -78 to +9 in the HSD17B1 gene serves as a promoter, and an HSD17B1 silencer element is located in position -113 to -78. In the present studies, we have characterized three regulatory elements in the proximal 5'-flanking regions of the gene, using electrophoretic mobility shift assays and reporter gene analysis. First, nuclear factors recognized by antibodies against Sp1 and Sp3 were found to bind the Sp1 motif in the region from -52 to -43. Mutation of the Sp1-binding site decreased the promoter activity to 30% in JEG-3 cells and to 60% in JAR cells, suggesting that binding to the Sp1 motif has a substantial role in the complete functioning of the HSD17B1 promoter. Second, the binding of AP-2 to its motif in the region from -62 to -53 led to reduced binding of Sp1 and Sp3, and furthermore, mutation of the AP-2 element increased promoter activity to 260% in JEG-3 cells. The data thus implied that AP-2 can repress the function of the HSD17B1 promoter by preventing binding to the Sp1 motif. Finally, GATA factors, GATA-3 in particular, were demonstrated to bind their cognate sequence in the HSD17B1 silencer region, and mutations introduced into the GATA-binding site increased transcriptional activity to the level seen in constructs not containing the silencer element. Thus, GATA-3 seems to prevent transcription in the constructs, and hence, the GATA motif also may operate as a negative control element for HSD17B1 transcription. PMID: 9231796 [PubMed - indexed for MEDLINE] ---------------------------------------------------------------