SEARCH · Search PubMed

Results for “TATA Box”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources

PubMed1994

Transcriptional activation of minimal HIV-1 promoter by ORF-1 protein expressed from the SalI-L fragment of human herpesvirus 6.

The SalI-L fragment of human herpesvirus 6 (HHV-6) strain U1102 transformed rodent cells and transactivated the HIV-1 LTR 10- to 15-fold in both monkey fibroblasts and human T-lymphocytes. In this report, the SalI-L transactivator of the HIV-1 LTR was localized to ORF-1 which codes for a protein of 357 amino acids. To determine if ORF-1 required functional Sp1 binding sites or the TATA box element of HIV-1 LTR for transactivation, 5'-deletion mutants of the HIV-1 LTR were employed. Plasmids pBS/SalI-L, pBS/SalI-L-SH, and pC6/ORF-1(S), a mammalian expression vector containing ORF-1, all transactivated a deletion mutant of HIV-1 LTR lacking functional Sp1 binding sites (CD-54). These studies demonstrate that transactivation occurred in the absence of Sp1 binding sites and required only a minimal HIV-1 promoter which contains the TATA box element. The specificity of the SalI-L transactivator for HIV-1 LTR was demonstrated by its inability to transactivate the human papillomavirus type 16 or 18 early promoters. The ORF-1 gene was cloned into and expressed from the pET17b bacterial expression vector. Purified ORF-1 protein was obtained by ammonium sulfate precipitation, Mono-S chromatography, and anti-T7. Tag immunoaffinity chromatography. Transactivation of the HIV-1 LTR by ORF-1 protein was demonstrated by electroporation studies in vivo and by transcription studies in vitro. To substantiate the putative biological role of ORF-1, pBS/SalI-L, pBS/SalI-L-SH, and pC6/ORF-1 all reactivated tat-defective HIV-1 provirus from latently infected cells expressing CD4. Thus, the data presented suggest that HHV-6 infection could have a cofactor role in the progression of AIDS.

Amino Acid Sequence↗

PubMed1993

Site-specific inhibition of RNA polymerase II preinitiation complex assembly by human cytomegalovirus IE86 protein.

The human cytomegalovirus major immediate-early gene encodes several protein isoforms which autoregulate the major immediate-early promoter (MIEP). One of these isoforms, the IE86 protein (UL122, IE2), is a DNA-binding protein that represses the MIEP through its cognate recognition sequence (designated the cis repression signal [crs]) located between the TATA box and the initiation site of transcription. Purified recombinant IE86 protein was shown to repress MIEP transcription in vitro, in a cis-acting mediated pathway, with nuclear extracts from HeLa S3, U373-MG, and primary human foreskin fibroblast cells. Repression of the MIEP by IE86 was shown by two criteria to be dependent on the direct interaction of IE86 with the crs element. Core promoter constructs containing essentially the MIEP TATA box and crs element were also specifically repressed by IE86 but not by a mutant IE86 protein, indicating the general transcription machinery as the target for IE86 repression. Kinetic and template commitment experiments demonstrated that IE86 affects preinitiation complex formation but not the rate of reinitiation. Sarkosyl inhibition experiments further revealed that IE86 was unable to effect repression by either disassembling or preventing the elongation of a preexisting transcription complex. Further, the ability of IE86 to interact with the DNA-binding subunit of TFIID was shown not to be required for repression. These functional protein-DNA and protein-protein interaction experiments demonstrate that IE86 specifically interferes with the assembly of RNA polymerase II preinitiation complexes. The biological significance of these results and the precise mechanism by which IE86 represses transcription are discussed.

Cell Nucleus↗

PubMed1990

Identification and characterization of an adenovirus 2 major late promoter CAP sequence DNA-binding protein.

DNase I footprint analysis of the core adenovirus 2 (Ad2) major late promoter (MLP) has revealed distinct patterns of protection corresponding to the assembly of transcription components during transcriptional initiation (VanDyke, M. W., Sawadogo, M., and Roeder, R. G. (1989) Mol. Cell Biol. 7, 3371-3379). By using partially purified transcription factors, DNase I protection over the TATA box element and the CAP sequence was attributed to the binding of a single factor, TFIID. We have determined, however, that protection of the CAP region results from the binding of a novel factor, designated CAP-site binding factor (CBF), which is chromatographically and functionally distinct from TFIID. DNase I footprint analysis and gel electrophoresis mobility shift competition assays confirm that distinct polypeptides bind to the Ad2 MLP upstream promoter sequence, TATA box, and CAP sequences. When the CAP sequence is mutated, transcriptional activity of the Ad2 MLP is reduced both in vitro and in vivo. The decrease in transcriptional activity correlates with decreased CBF binding activity. Nuclear extracts depleted of CBF also exhibit reduced Ad2 MLP transcriptional activity. The addition of DNA affinity purified CBF, free of TFIID or major late transcription factor, restores the activity to control levels.

Adenoviruses, Human↗

PubMed2000

A map of protein-protein contacts within the small nuclear RNA-activating protein complex SNAPc.

The nucleation of RNA polymerases I-III transcription complexes is usually directed by distinct multisubunit factors. In the case of the human RNA polymerase II and III small nuclear RNA (snRNA) genes, whose core promoters consist of a proximal sequence element (PSE) and a PSE combined with a TATA box, respectively, the same multisubunit complex is involved in the establishment of RNA polymerase II and III initiation complexes. This factor, the snRNA-activating protein complex or SNAP(c), binds to the PSE of both types of promoters and contains five types of subunits, SNAP190, SNAP50, SNAP45, SNAP43, and SNAP19. SNAP(c) binds cooperatively with both Oct-1, an activator of snRNA promoters, and in the RNA polymerase III snRNA promoters, with TATA-binding protein, which binds to the TATA box located downstream of the PSE. Here we have defined subunit domains required for SNAP(c) subunit-subunit association, and we show that complexes containing little more than the domains mapped here as required for subunit-subunit contacts bind specifically to the PSE. These data provide a detailed map of the subunit-subunit interactions within a multifunctional basal transcription complex.

Amino Acid Sequence↗

PubMed1988

UV-inducible transient expression in parsley protoplasts identifies regulatory cis-elements of a chimeric Antirrhinum majus chalcone synthase gene.

It was shown previously that parsley protoplasts retain differential responsiveness to external stimuli, e.g. UV light. This opened the way for the development of transient expression assays to identify DNA sequences acting as regulatory cis-elements in the transcriptional activation of UV-inducible plant genes. The chalcone synthase (chs) gene of Antirrhinum majus (Snapdragon) is inducible by visible and by UV light. We demonstrate that the kinetics of light induction of a chimeric A.majus chs-nptII gene observed during transient expression in the parsley protoplasts reflect the kinetics of UV-induced CHS expression in A.majus seedlings in vivo. We define three regulatory sequence regions, each differing qualitatively and quantitatively in their effects on gene expression. Immediately upstream of the TATA box (-34) a sequence, with coordinates -39 to -197, functions as an orientation independent UV-light responsive element. The complete 1.1 kb promoter or three tandem copies of this element are capable of rendering a heterologous minimal promoter UV responsive. The next upstream region (-197 to -357) contains sequences that do not by themselves cause UV-induced expression, but specifically potentiate the level of UV-induced expression when combined with the TATA-box proximal UV-responsive element. A third element (-661 to -564) has the properties of a general enhancer since it increases the level of both uninduced and UV-induced expression.

Journal Article↗

PubMed1989

Herpes simplex virus type 2 mutants with deletions in the intergenic region between ICP4 and ICP22/47: identification of nonessential cis-acting elements in the context of the viral genome.

In herpes simplex virus type 2, the mRNAs of ICP4 and ICP22/47 are divergently transcribed and their transcription initiation sites are separated by 750 base pairs (L. J. Whitton and J. B. Clements, Nucleic Acids Res. 12:2061-2078, 1984). This 750-base-pair region contains many recognized cis-acting elements, including two TATA boxes, numerous Sp1-binding sites, four TAATGARAT motifs, at least one ICP4-binding site, and two origins of replication (oriS) linked in tandem. In this report, we describe the construction of mutant viruses with defined deletions that eliminate these elements either singly or in combination. The phenotypic properties of these mutants indicate that (i) the TAATGARAT motifs and their neighboring elements affect the levels of transcription of both ICP4 and ICP22/47 similarly, (ii) the TATA box serving ICP4 is required for efficient ICP4 mRNA synthesis and for determining the initiation site of transcription, (iii) the ICP4-binding site located at the start of ICP4 transcription is at least partially responsible for the decreased levels of ICP4 mRNA observed in the presence of immediate-early and early gene products, and (iv) mutants bearing deletions that eliminate the entire conventionally recognized ICP4 promoter generate sufficient ICP4 mRNA to maintain viability in cells not expressing ICP4. Additionally, our inability to generate viable deletion mutants lacking all copies of oriS suggests that at least one copy of oriS may be essential for virus replication.

Chromosome Deletion↗

PubMed1993

The quail tyrosine hydroxylase gene promoter contains an active cyclic AMP-responsive element.

A 1.5-kb genomic DNA fragment situated upstream from the quail tyrosine hydroxylase (TH) gene transcription site was isolated. This upstream region starts 15 bp from the translation initiation site. It contains two canonical TATA boxes, at positions -37 and -297, three putative glucocorticoid-responsive elements, at positions -1487, -1329, and -1268, and one putative cyclic AMP (cAMP)-responsive element (CRE) at position -53, as well as a putative negative regulatory element consensus sequence at position -735. The consensus POU-Oct site is partly conserved. Comparison of the 5' flanking sequences of quail and mammalian (bovine, human, and rat) TH genes revealed a strong sequence conservation within the 230 nucleotides upstream of the TATA box, with a distinct conservation of the CRE region. Constructs in which the bacterial chloramphenicol acetyltransferase (CAT) reporter gene was linked to promoter stretches of increasing lengths were transfected into three cell lines, two of them originating from quail and rat neural crest and the third derived from mouse fibroblasts. Reporter gene expression was specifically high in the quail and rat neural crest-derived cells compared to the fibroblast cell line. The physiological activity of this putative quail CRE was analyzed further in transfected neural crest cells of quail origin. Both cAMP analogues and agents that enhance intracellular cAMP increased CAT activity. The physiological relevance of this finding is sustained by the presence, in quail nuclear extracts, of a protein(s) that binds CRE consensus sequences.

Animals↗

PubMed1997

Transcriptional regulation of the TGF-beta 2 gene in choriocarcinoma cells and breast carcinoma cells: differential utilization of Cis-regulatory elements.

Previous studies have shown that the transcription of the TGF-beta 2 gene is controlled by at least one negative and two positive regulatory regions in differentiated cells derived from both embryonal carcinoma cells and embryonic stem cells. The use of TGF-beta 2 promoter/reporter gene constructs has also identified a CRE/ATF motif near the TATA box that appears to heavily influence the transcription of the TGF-beta 2 gene. In this study, two choriocarcinoma cell lines, JAR and JEG-3, and the breast cancer cell line, MCF-7, were used to determine whether differences exist in the transcriptional regulation of the TGF-beta 2 gene. We demonstrated that both similarities and differences exist in the transcriptional regulation of this gene. Common to all cells examined to date, the positive regulatory region just upstream of the TATA box contains an essential CRE/ATF motif that binds at least one transcription factor, ATF-1, in gel mobility shift assays. However, we did not detect ATF-2 binding to this site with any of the nuclear extracts used. We also determined that the effect of the region between -187 and -78 (relative to the transcription start site) is cell type dependent. Previous studies have shown that this region acts to reduce the activity of the TGF-beta 2 promoter in differentiated cells derived from embryonal carcinoma cells and embryonic stem cells. In direct contrast, this region acts as a strong positive regulatory region in JAR, JEC-3, and MCF-7 cells. The mechanisms responsible for these differing effects remain to be established. Interestingly, this region does not appear to contain sequence motifs that bind known transcription factors. Thus, this region is likely to bind one or more novel transcription factors or contain novel recognition sites for known transcription factors.

Activating Transcription Factor 1↗

PubMed1993

Human cytomegalovirus IE86 protein interacts with promoter-bound TATA-binding protein via a specific region distinct from the autorepression domain.

The major immediate-early gene of human cytomegalovirus encodes several isoforms of an immediate-early protein which has distinct transcriptional regulatory properties. The IE86 isoform autorepresses the major immediate-early promoter by directly binding the cis repression signal element located between the TATA box and the mRNA cap site. In addition to this activity, IE86 stimulates other viral and cellular promoters. One mechanism by which eukaryotic regulatory proteins are thought to stimulate transcription is by contacting one or more general transcription factors. We show that the IE86 protein physically interacts with the DNA-binding subunit (TATA-binding protein) human transcription factor IID via the TATA-binding protein-contacting domain in the N terminus of IE86. In a mobility shift assay, IE86 was also observed to stabilize the binding of TATA-binding protein to promoter DNA. The domains within IE86 responsible for mediating transactivation and repression functioned independently. These experiments thus demonstrate the elegant ability of human cytomegalovirus to join different protein domains to produce distinct multifunctional proteins.

Base Sequence↗

PubMed2003

Expression of a structurally unique osteoclastic protein-tyrosine phosphatase is driven by an alternative intronic, cell type-specific promoter.

An osteoclastic protein-tyrosine phosphatase (PTP-oc), essential for osteoclast activity, shows sequence identity with the intracellular domain of GLEPP1, a renal receptor-like transmembrane PTP. PTP-oc has been assumed to be a truncated variant of GLEPP1, resulting from alternative splicing. However, the 5'-untranslated region sequence of PTP-oc mRNA contains 217 bp from an intron of GLEPP1. There are no splicing acceptor sites at the PTP-oc transcription site. The intronic sequence flanking the 5' end of the PTP-oc transcription start site contains potential promoter elements essential for transcriptional initiation. To test the hypothesis that the PTP-oc gene has an alternative, tissue-specific, intronic promoter, the promoter activity of a 1.3-kb PCR fragment covering the 5'-flanking region of the PTP-oc gene was measured. The putative PTP-oc promoter fragment showed strong promoter activity in U937 cells. Mutation of the putative TATA box within the PTP-oc promoter abolished 60-90% of its promoter activity. The PTP-oc promoter fragment showed strong promoter activity in cells that express PTP-oc (U937 cells and RAW264.7 cells) but not in cells that do not express the enzyme (skin fibroblasts, TE85 cells, and HEK293 cells). These findings strongly support the conclusion that the 1.3-kb intronic fragment contains the tissue-specific, PTP-oc proximal promoter. Deletion and functional analyses indicate that the proximal 5' sequence flanking the TATA box of the PTP-oc contains potential repressor elements. The removal of the putative repressor elements led to the apparent loss of tissue specificity. In summary, we conclude that an intronic promoter within the GLEPP1 gene drives the expression of the PTP-oc in a cell type-specific manner. This GLEPP1/PTP-oc gene system is one of the very few systems in which two important tissue-specific enzymes are derived from the same gene by the use of alternative intronic promoters.

Alternative Splicing↗

PubMed1991

A cis-acting element in the major immediate-early (IE) promoter of human cytomegalovirus is required for negative regulation by IE2.

The major immediate-early promoter (MIEP) of human cytomegalovirus (CMV) contains a number of different enhancer elements in both repetitive and nonrepetitive sequences that influence the level of downstream transcription. This report describes a cis-acting element in the MIEP that responds to negative regulation by the IE2 gene product. Deletion analysis demonstrated that the cis-acting repressor element is located between the TATA box and the transcription initiation site from -13 to -1. The DNA sequence of the repressor element is 5'-CGTTTAGTGAACC-3'. The sequence is found in both the human and simian CMV MIEPs but not the murine CMV MIEP or in several other enhancer-containing promoters. The repressor element was isolated in a DNA fragment from -13 to +3 and was found to be functional in either orientation. It could be transferred to a heterologous enhancer-containing promoter and was functional when placed between the TATA box and the transcription initiation site. The element did not function when placed downstream of the transcription initiation site. Therefore, the cis-acting repressor element is position dependent. The role of the repressor element and the IE2 gene product in human CMV productive or latent infection is discussed.

Base Sequence↗

PubMed1998

Transcriptional activity of the hamster CYP11B2 promoter in NCI-H295 cells stimulated by angiotensin II, potassium, forskolin and bisindolylmaleimide.

We studied the regulation of the hamster CYP11B2 gene in the NCI-H295 cell line, which is known to produce aldosterone in response to stimulation by angiotensin II (AII) and KCl. Ten deletion plasmids harboring the 5'-untranslated region of the CYP11B2 gene were used for chloramphenicol acetyltransferase (CAT) assays. Transient transfections showed progressively increasing basal promoter activity by constructs beyond the TATA box, with a peak occurring with the -167 bp construct which contains putative Adl, Ad2, Ad5 and the newly reported -143/-161 cis-element sequences. The promoter activity was lower with the construct containing the putative Ad3 cis-element and increased with longer constructs. This indicates the presence of both inhibitory and stimulatory cis-elements in this area of the gene. Expression of the reporter gene of all constructs was stimulated by AII and KCl, with the exception of the construct containing only the TATA box, which showed 6-fold and 10-fold increases occurring with the -167 bp deletion plasmid. The patterns of increase in CAT activity with AII and KCI treatment were similar, showing that these two regulators can stimulate hamster CYP11B2 promoter activity through common cis-elements. The calcium channel antagonist nifedipine blocked the stimulatory effects of KCl on CAT activity, showing the involvement of calcium channels in the regulation of CYP11B2 gene transcription by KCl. 12-O-Tetradecanoylphorbol 13-acetate, a known stimulator of the protein kinase C (PKC) signaling pathway, was without significant effect on CAT activity. Bisindolylmaleimide, a specific inhibitor of PKC, had a significant enhancing effect (3.4- to 6-fold), indicating that PKC may negatively regulate the expression of the hamster CYP11B2 gene in NCI-H295 cells. A mutation was induced in the sequence -143/-161 of the - 350 bp construct in order to determine its importance in the regulation of hamster CYP11B2 promoter activity. The stimulatory effects of AII, KCl, forskolin and bisindolylmaleimide on CAT activity were significantly less in the mutant than in the wild type. These results confirm that this cis-element is necessary in maintaining a high level of transcriptional activity in stimulated NCI-295H cells. In conclusion, using NCI-295H transfected cells, we have found that the 5'-untranslated region of the hamster CYP11B2 gene possesses transcriptional activity with stimulatory and also inhibitory cis-elements; CYP11B2 promoter activity can be stimulated by AII, KCl, forskolin, dibutyryl cAMP and bisindolylmaleimide. Our results suggest that this gene is positively regulated through the protein kinase A signaling pathway and through calcium channels, whereas PKC may have a negative regulatory effect upon the transcription of the CYP11B2 gene. Furthermore, we have shown that the cis-element -143/-161 in the 5'-untranslated region of the hamster CYP11B2 gene is important in maintaining a high level of promoter activity in stimulated NCI-295H cells.

Aldosterone↗

PubMed1998

Characterization of cis-acting and NS1 protein-responsive elements in the p6 promoter of parvovirus B19.

Parvovirus B19 infections are associated with diverse clinical manifestations, ranging from no symptoms to severe symptoms. The virus shows an extreme tropism for replication in erythroid progenitor cells, possibly due to the activity of the only functional promoter (p6) of the B19 virus genome in combination with both cell- and cell cycle-specific factors and the trans-activator protein NS1. As presented here, p6 promoter sequences derived from several B19 virus isolates proved to be highly conserved. Furthermore, mutations did not affect any of the potential binding sites for transcription factors. One variation of the base at position 223 was identified only in B19 virus isolates derived from patients with persistent infection or chronic arthritis. To determine promoter activity and to characterize regulatory elements, sequences spanning the total p6 promoter and subfragments of them were introduced into a eukaryotic expression vector upstream of the luciferase gene (from Photinus pyralis). After transfection into HeLa, CEM, BJAB, and K562 cells, the p6 promoter was found to be highly active. When introduced into the erythroid cell line K562, p6-controlled transcription exceeded that of the simian virus 40 promoter-enhancer used as a control by more than 25-fold. Sequence elements relevant for promoter activity mapped to the regions from nucleotides (nt) 100 to 190 and 233 to 298. Also, the segment from nt 343 to 400 downstream of the TATA box was important for transcriptional activity in HeLa and K562 cells. By transfecting the promoter-luciferase constructs into a HeLa cell line stably carrying the viral NS1 gene under the control of an inducible promoter, transcriptional activity mediated by the p6 promoter rose significantly after induction of NS1 expression. The region from nt 100 to 160 proved to be essential for NS1-mediated transcriptional activation. Furthermore, NS1-mediated transactivation was dependent on the presence of two GC-rich elements arranged in tandem upstream of the TATA box. These data indicate that NS1-mediated p6 transactivation is dependent on a multicomponent complex combining NS1 with ATF, NF-kappaB/c-Rel, and GC-box binding cellular factors.

Base Sequence↗

PubMed1999

DNA binding site selection by RNA polymerase II TAFs: a TAF(II)250-TAF(II)150 complex recognizes the initiator.

Basal transcription factor TFIID comprises the TATA-box-binding protein, TBP, and associated factors, the TAF(II)s. Previous studies have implicated TAF(II)250 and TAF(II)150 in core promoter selectivity of RNA polymerase II. Here, we have used a random DNA binding site selection procedure to identify target sequences for these TAFs. Individually, neither TAF(II)250 nor TAF(II)150 singles out a clearly constrained DNA sequence. However, a TAF(II)250-TAF(II)150 complex selects sequences that match the Initiator (Inr) consensus. When in a trimeric complex with TBP, these TAFs select Inr sequences at the appropriate distance from the TATA-box. Point mutations that inhibit binding of the TAF(II)250-TAF(II)150 complex also impair Inr function in reconstituted basal transcription reactions, underscoring the functional relevance of Inr recognition by TAFs. Surprisingly, the precise DNA sequence at the start site of transcription influences transcriptional regulation by the upstream activator Sp1. Finally, we found that TAF(II)150 specifically binds to four-way junction DNA, suggesting that promoter binding by TFIID may involve recognition of DNA structure as well as primary sequence. Taken together, our results establish that TAF(II)250 and TAF(II)150 bind the Inr directly and that Inr recognition can determine the responsiveness of a promoter to an activator.

Amino Acid Sequence↗

PubMed1984

Generation and functional analyses for base-substitution mutants of the adenovirus 2 major late promoter.

The function of guanosine residues surrounding the TATA box of the adenovirus 2 major late promoter (MLP) in promoting efficient transcription initiation and in selecting a specific transcription start site in vitro has been examined. Multiple and single base substitutions (G----A) were generated in this region (from -63 to +25 relative to the cap site, +1) of the MLP. The promoter activities of the wild type and 21 mutants were assayed in an in vitro transcription system using whole cell extract (WCE) prepared from HeLa cells. The results suggest that the strings of G residues immediately adjacent to the TATA box are not required for full promoter activity in vitro. These G residues also appear not to be involved in the selection of a specific transcription start site by RNA polymerase II in vitro, since the identical cap site was used by wild-type and mutated MLP's. However, two G residues (-55 and -57) were identified as part of an upstream promoter element: a G----A transition at either -55 or -57 resulted in a 2.6 fold reduction in promoter activity. However, neither single nor double G----A transitions at -62 and -63 had an effect on promoter activity.

Adenoviruses, Human↗

PubMed1998

The tyrosinase gene from medakafish: transgenic expression rescues albino mutation.

We have determined the 9.8 kb genomic nucleotide sequence of the tyrosinase gene and its 5 upstream region from a teleost, medakafish (Oryzias latipes), and shown that the coding region is composed of five exons and four introns, spanning 4.7 kb. While the number and sizes of the exons were found to be similar to those of mammalian tyrosinase genes, however, the total size of the coding region (4.7 kb) was demonstrated to be less than one tenth those of mouse (ca. 70 kb) and human (> 70 kb) genes. Primer extension analysis revealed that the transcription initiation site starts with a long untranslated leader sequence (340 nucleotide long) from the AUG start codon. A characteristic CATGTG sequence known as a putative regulatory motif in melanocyte-specific genes was present in the 131st base upstream from the initiation site, while other typical regulatory elements such as the TATA-box or M-box common to terrestrial vertebrates were lacking. Transgenic experiments were carried out by microinjecting two kinds of plasmid clones into fertilized eggs of the albino i(l) mutant: one consisting of the genomic tyrosinase gene with the 10 kb 5 upstream region and the other the tyrosinase cDNA with the 3 kb 5 upstream region. The results showed that 53 and 45 of 114 and 118 transgenic eggs, respectively, developed normally beyond hatching and 15 and 10 exhibited a mosaic pattern of pigmentation. Despite the absence of typical regulatory elements like a TATA-box in both cases correct melanin pigmentation was obtained without ectopic expression. Thus, transgenic expression rescued from the albino-i(l) mutation, and the i locus of the medaka genome can be concluded to encode the tyrosinase gene.

Albinism↗

PubMed1986

Structural analysis of the X-linked gene encoding human glucose 6-phosphate dehydrogenase.

We report the isolation and analysis of human genomic DNA clones spanning about 100 kb of the X chromosome and comprising the entire gene coding for the enzyme glucose 6-phosphate dehydrogenase (G6PD). The G6PD gene is 18 kb long and consists of 13 exons: the protein-coding region is divided into 12 segments ranging in size from 12 to 236 bp; an intron is present in the 5' untranslated region. Mature G6PD mRNA has a single polyadenylation site in HeLa cells. The major 5' end of mature G6PD mRNA in several cell lines is located 177 bp upstream of the translation initiating codon; longer mRNA molecules extending further in the 5' direction could be identified by S1 mapping and by comparing genomic and cDNA sequences. The DNA sequence around the major mRNA start is very GC rich; as to putative transcription regulatory sequences, a non-canonical TATA box and 9 CCGCCC elements are present, but no CAAT element could be identified. The genomic DNA we have isolated includes another ubiquitously transcribed region, provisionally named the GdX gene. Although the function of GdX is as yet unknown, we have established that this gene is located about 40 kb downstream of G6PD and is transcribed in the same direction. A comparative analysis of the promoter region of G6PD and 10 other housekeeping enzyme genes has confirmed the presence of a number of common features. In particular, in the eight cases in which a 'TATA' box is present, a conserved sequence of 25 bp is seen immediately downstream.

Base Sequence↗

PubMed1996

Characterization of the mouse epidermal growth factor promoter and 5'-flanking region. Role for an atypical TATA sequence.

As a step toward delineating mechanisms that regulate its activity, we have characterized the mouse epidermal growth factor (EGF) promoter. Primer extension and S1 nuclease analyses identified prominent (+1/+2) and minor (+28) transcription start sites, with the dominant +1/+2 site located 33 bases downstream from a TTTAAA sequence. A restriction fragment that spanned these start sites and contained 390 base pairs of 5'-flanking sequence directed transcription from the +1/+2 site in vitro in the presence of HeLa cell nuclear extracts. Additionally, it promoted expression of a coupled luciferase reporter gene in transfected cell lines. The inclusion of additional 5'-flanking sequence either stimulated or inhibited luciferase expression depending on the cell line. Approximately 2 kilobases of EGF 5'-flanking sequence was determined and found to contain several motifs with partial homology to steroid hormone response elements. Despite this fact and evidence that EGF expression might be regulated by androgens in vivo, EGF promoter-luciferase constructs were not steroid-responsive in cells cotransfected with steroid receptor expression vectors. An oligonucleotide containing the aforementioned TTTAAA sequence specifically bound TATA-binding protein and TFIIA in gel shift assays, and an EGF promoter-luciferase construct in which the core TA dinucleotide was mutated to CG was not active in transfected cells. These data suggest that the TTTAAA sequence functions as an atypical TATA box.

Androgens↗