Exocrine pancreas transcription factor 1 binds to a bipartite enhancer element and activates transcription of acinar genes.

Weinrich, S L; Meister, A; Rutter, W J

doi:10.1128/mcb.11.10.4985

Cited by 14 publications

(8 citation statements)

References 41 publications

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“…This pattern is reminiscent of bipartite binding sites that often possess intervening DNase I hypersensitive sites (Weinrich et al, 1991;Ramji et al, 1991). Taken together, these data indicate that the 210 mM KCI fraction contains protein(s) that binds specifically to the GARE and box I.…”

Section: Discussionmentioning

confidence: 58%

Gibberellin Treatment Stimulates Nuclear Factor Binding to the Gibberellin Response Complex in a Barley a-Amylase Promoter

Sutliff¹,

Lanahan²,

Ho³

1993

The Plant Cell

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The promoters of a majority of cereal a-amylase genes contain three highly conserved sequences (gibberellin response element, box I, and pyrimidine box). Recent studies have demonstrated the functional importance of four regions that either coincide with orare immediately proximal to these three conserved elements as well as an upstream Opaque-2 binding sequence. In this study, we describe the characterization of nuclear protein factors from barley aleurone layers whose binding activity toward gibberellin response complex sequences from the barley low-pl a-amylase gene (Amy32b) promoter is stimulated by gibberellin A3 (a3) treatment. Barley proteins isolated from crude nuclear extracts prepared from aleurone layers incubated with or without GA3 were fractionated by anion exchange fast protein liquid chromatography and studied using band shift assays, sequence-specific competitions, and DNase I footprinting. A GA3-dependent binding activity eluting at 210 mM KCI was shown to bind specifically to the gibberellin response element and the closely associated box 1. DNase I footprinting with the proteins in this fraction indicated interactions with sequences in the gibberellin response element and box 1. A second DNA binding activity eluting at 310 mM KCI was present constitutively in extracts prepared from tissues incubated both in the absence and in the presence of hormone. Proteins in this fraction were able to bind to many DNA sequences and, in general, were largely nonspecific. DNase I footprinting with the proteins in this fraction indicated a large ama of protection with a single unoccupied region located at the 3' end of box 1. The possible function of such an activity in hormone regulation of the a-amylase genes is discussed.

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Section: Discussionmentioning

confidence: 58%

Gibberellin Treatment Stimulates Nuclear Factor Binding to the Gibberellin Response Complex in a Barley a-Amylase Promoter

Sutliff¹,

Lanahan²,

Ho³

1993

The Plant Cell

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“…These observations indicate that PTF1, through binding to the PCE, is the principal determinant for the transcription of acinar cell-specific genes, although other transcriptional elements (e.g., the B and C elements of the EI enhancer) in the regulatory regions of the acinar genes are required for activity in both cultured cells (13) and animals (34). Weinrich et al (36) have characterized a similar PCE-binding activity (XPF1), although its relationship with PTF1 and its role in pancreatic gene activation are not yet clear.…”

Section: Discussionmentioning

confidence: 99%

Cooperation between Elements of an Organ-Specific Transcriptional Enhancer in Animals

Kruse

Rose

Swift

et al. 1995

Molecular and Cellular Biology

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The elastase I gene enhancer that specifies high levels of pancreatic transcription comprises three functional elements (A, B, and C). When assayed individually in transgenic mice, homomultimers of A are acinar cell specific, those of B are islet specific, and those of C are inactive. To determine how the elements interact in the elastase I enhancer and to investigate further the role of the C element, we have examined the activity of the three possible combinations of synthetic double elements in transgenic animals. Combining the A and B elements reconstitutes the exocrine plus endocrine specificity of the intact enhancer with an increased activity in acinar cells compared with that in the A homomultimer. The B element therefore plays a dual role: in islet cells it is capable of activating transcription, whereas in acinar cells it is inactive alone but greatly augments the activity specified by the A element. The C element augments the activity of either the A or B element without affecting their pancreatic cell type specificity. The roles of each element were verified by examining the effects of mutational inactivation of each element within the context of the elastase I enhancer. These results demonstrated that when tested in animals, the individual enhancer elements can perform discrete, separable functions that combine additively for cell type specificity and cooperatively for the overall strength of a multielement stage-and site-specific transcriptional enhancer.The elastase I (EI) gene is one of the pancreatic digestive enzyme genes which are activated in a stage-and site-specific manner during development of the mammalian gut. EI mRNA is present at very high levels in pancreatic acinar cells, equivalent to approximately 1% of the mRNA population, and at 100-to 1,000-fold-lower levels in other parts of the gastrointestinal tract including the stomach, duodenum, and colon (16,26). EI mRNA first becomes detectable in the pancreas at about embryonic day 14 in rats (9), about 4 days after the appearance of the pancreatic bud on the developing gut. The transcriptional regulatory regions that confer this organ-and stage-specific expression lie immediately upstream of the EI structural gene (14,22). This region includes a 134-bp enhancer (Ϫ72 to Ϫ205) that is both necessary and sufficient for the spectrum of gastrointestinal transcription (8, 26) and a TATA box-containing promoter (ϩ8 to Ϫ71) that does not contribute to organ specificity (21, 26). Although organ specific, the isolated enhancer directs expression inappropriately to islet cells as well as acinar cells (14). The acinar cell specificity notable for the endogenous gene is enforced by a negative regulatory region immediately upstream of the enhancer (Ϫ206 to Ϫ501) that selectively suppresses islet cell expression.The EI transcriptional enhancer contains three functional elements (A, B, and C) of 12 to 25 bp each (26, 35). When multimerized, the A and B elements can direct the activation of a naive reporter gene in the pancreas of transgenic mice (14, ...

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“…Affinity purification using the chymotrypsin PCE yielded a 60-kDa protein, XPF-1, that binds to both the A and B boxes (41). The DNase I footprint of XPF-1 covers the A and B boxes not only of chymotrypsin B but also of El and amylase 2.1.…”

Section: Discussionmentioning

confidence: 99%

A single element of the elastase I enhancer is sufficient to direct transcription selectively to the pancreas and gut.

Rose¹,

Kruse²,

Swift³

et al. 1994

Mol. Cell. Biol.

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The elastase I (El) gene is expressed at high levels in the exocrine pancreas and at lower levels in other regions of the gut. The transcriptional enhancer of the EI gene, from nucleotides -205 to -72, recapitulates the expression of the endogenous gene in transgenic mice; it directs not only pancreatic acinar cell expression of a human growth hormone (hGH) transgene but also expression to the stomach, duodenum, and colon. This pattern of selective expression limited to the gastroenteropancreatic organ system is specified by the A element, one of three functional elements in the El enhancer. When multimerized, the A element directed expression of a hGH reporter gene selectively to the pancreas, stomach, and intestine in transgenic mice. Immunofluorescent localization of hGH indicated that the A element multimer transgenes were expressed in the acinar cells of the pancreas as well as in Brunner's gland cells of the duodenum. The A element binds a pancreatic acinar cell-specific factor, PIF1. Our results show that while the A element is responsible for directing tissue and cell type specificity, other elements of the enhancer must be involved in the regulation of the level of gene expression.Cell-specific transcriptional enhancers are complex assemblies of multiple DNA elements and their bound transcription factors. To understand their mechanism of action, it is necessary to understand the role of the individual functional elements and their bound factors in controlling the cell type and strength of activation of the basal transcriptional machinery at the promoter. The tissue-specific transcriptional enhancer of the pancreatic elastase I (El) gene confers high-level expression in transgenic mice independent of its position relative to the promoter and with a heterologous promoter (15). The enhancer forms a tissue-specific chromatin DNase I-hypersensitive site indicative of a nucleoprotein transcription complex which follows the enhancer when it is moved in transgene constructs either near the promoter, far upstream, or within the reporter gene.The minimal region that retains these properties spans 134 bp (from -72 to +205) and is composed of three functional elements (A, B, and C). All three elements are necessary for expression in cultured pancreatic acinar cells (20) and important in pancreatic expression in transgenic mice (38). The A element comprises the pancreatic consensus element (PCE), a 17-bp sequence found in the 5' flanking region of other pancreatic acinar cell digestive enzyme genes as well (2,8,37 648-8856. amylase gene was used to partially purify a binding activity from pancreatic nuclear extracts (6). This binding activity, designated PTF1, is specific for DNA sequences containing a PCE (6, 16). PTF1 contains two DNA-binding proteins, a 48-kDa subunit which binds to the A box and a 64-kDa subunit which binds to the B box (34). The appearance of PTF1 during the development of the mouse pancreas coincides with the onset of expression of the digestive enzyme genes (32). These observations sugg...

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Exocrine pancreas transcription factor 1 binds to a bipartite enhancer element and activates transcription of acinar genes.

Cited by 14 publications

References 41 publications

Gibberellin Treatment Stimulates Nuclear Factor Binding to the Gibberellin Response Complex in a Barley a-Amylase Promoter

Gibberellin Treatment Stimulates Nuclear Factor Binding to the Gibberellin Response Complex in a Barley a-Amylase Promoter

Cooperation between Elements of an Organ-Specific Transcriptional Enhancer in Animals

A single element of the elastase I enhancer is sufficient to direct transcription selectively to the pancreas and gut.

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