The cell-specific elastase I enhancer comprises two domains

1988 ◽  
Vol 8 (2) ◽  
pp. 893-902 ◽  
Author(s):  
F Kruse ◽  
C T Komro ◽  
C H Michnoff ◽  
R J MacDonald
Keyword(s):  
Base Pair ◽  
Regulatory Region ◽  
Acinar Cells ◽  
Chloramphenicol Acetyltransferase ◽  
Pancreatic Tissue ◽  
Pancreatic Acinar Cells ◽  
Specific Expression ◽  
Nuclear Extracts ◽  
Dna Strands ◽  
Rat Elastase

Two separate domains within the 134-base-pair rat elastase I enhancer and a third domain at the enhancer-promoter boundary are required for selective expression in pancreatic acinar cells. The domains were detected by a series of 10-base-pair substitution mutations across the elastase I gene regulatory region from positions -200 to -61. The effect of each mutant on the pancreas-specific expression of a linked chloramphenicol acetyltransferase gene was assayed by transfection into pancreatic 266-6 acinar cells and control NIH/3T3 cells. The two enhancer domains are nonredundant, because mutations in either eliminated (greater than 100-fold reduction) expression in 266-6 cells. DNase I protection studies of the elastase I enhancer-promoter region with partially purified nuclear extracts from pancreatic tissue and 266-6 cells revealed nine discrete protected regions (footprints) on both DNA strands. One of three footprints that lie within the two functional domains of the enhancer contained a sequence, conserved among several pancreas-specific genes, which when mutated decreased linked chloramphenicol acetyltransferase expression up to 170-fold in 266-6 cells. This footprint may represent a binding site for one or more pancreas-specific regulatory proteins.

scholarly journals The cell-specific elastase I enhancer comprises two domains.

1988 ◽  
Vol 8 (2) ◽  
pp. 893-902 ◽  
Author(s):  
F Kruse ◽  
C T Komro ◽  
C H Michnoff ◽  
R J MacDonald
Keyword(s):  
Base Pair ◽  
Regulatory Region ◽  
Acinar Cells ◽  
Chloramphenicol Acetyltransferase ◽  
Pancreatic Tissue ◽  
Pancreatic Acinar Cells ◽  
Specific Expression ◽  
Nuclear Extracts ◽  
Dna Strands ◽  
Rat Elastase

Two separate domains within the 134-base-pair rat elastase I enhancer and a third domain at the enhancer-promoter boundary are required for selective expression in pancreatic acinar cells. The domains were detected by a series of 10-base-pair substitution mutations across the elastase I gene regulatory region from positions -200 to -61. The effect of each mutant on the pancreas-specific expression of a linked chloramphenicol acetyltransferase gene was assayed by transfection into pancreatic 266-6 acinar cells and control NIH/3T3 cells. The two enhancer domains are nonredundant, because mutations in either eliminated (greater than 100-fold reduction) expression in 266-6 cells. DNase I protection studies of the elastase I enhancer-promoter region with partially purified nuclear extracts from pancreatic tissue and 266-6 cells revealed nine discrete protected regions (footprints) on both DNA strands. One of three footprints that lie within the two functional domains of the enhancer contained a sequence, conserved among several pancreas-specific genes, which when mutated decreased linked chloramphenicol acetyltransferase expression up to 170-fold in 266-6 cells. This footprint may represent a binding site for one or more pancreas-specific regulatory proteins.

scholarly journals A novel cis-acting element controlling the rat CYP2D5 gene and requiring cooperativity between C/EBP beta and an Sp1 factor.

1994 ◽  
Vol 14 (2) ◽  
pp. 1383-1394 ◽  
Author(s):  
Y H Lee ◽  
M Yano ◽  
S Y Liu ◽  
E Matsunaga ◽  
P F Johnson ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Ternary Complex ◽  
Sequence Similarity ◽  
Consensus Sequence ◽  
Regulatory Region ◽  
Mrna Levels ◽  
Binding Studies ◽  
Mobility Shift ◽  
Specific Expression ◽  
Nuclear Extracts

The rat CYP2D5 gene encodes a cytochrome P450 and is expressed in liver cells. Its expression commences a few days after birth, and maximal mRNA levels are achieved when animals reach puberty. Transfection and DNA binding studies were performed to investigate the mechanism controlling developmentally programmed, liver-specific expression of CYP2D5. Transfection studies using a series of CYP2D5 upstream DNA chloramphenicol acetyltransferase gene fusion constructs identified a segment of DNA between nucleotides -55 and -156 that conferred transcriptional activity in HepG2 cells. Activity was markedly increased by cotransfection with a vector expressing C/EBP beta but was unaffected by vectors producing other liver-enriched transcription factors (C/EBP alpha, HNF-1 alpha, and DBP). DNase I footprinting revealed a region protected by both HepG2 and liver cell nuclear extracts between nucleotides -83 and -112. This region displayed some sequence similarity to the Sp1 consensus sequence and was able to bind the Sp1 protein, as assessed by a gel mobility shift assay. The role of Sp1 in CYP2D5 transcription was confirmed by trans activation of the 2D5-CAT construct in Drosophila melanogaster cells by using an Sp1 expression vector. C/EBP beta alone was unable to directly bind the -83 to -112 region of the promoter but was able to produce a ternary complex when combined with HepG2 nuclear extracts or recombinant human Sp1. C/EBP alpha was unable to substitute for C/EBP beta in forming this ternary complex. A poor C/EBP binding site is present adjacent to the Sp1 site, and mutagenesis of this site abolished formation of the ternary complex with the CYP2D5 regulatory region. These result establish that two transcription factors can work in conjunction, possibly by protein-protein interaction, to activate the CYP2D5 gene.

scholarly journals Impaired autophagy increases susceptibility to endotoxin-induced chronic pancreatitis

2020 ◽  
Vol 11 (10) ◽  
Author(s):  
L. Xia ◽  
Z. Xu ◽  
X. Zhou ◽  
F. Bergmann ◽  
N. Grabe ◽  
...  
Keyword(s):  
Chronic Pancreatitis ◽  
Lethal Dose ◽  
Acinar Cells ◽  
Pancreatic Injury ◽  
Pancreatic Tissue ◽  
Pancreatic Acinar Cells ◽  
Chromogenic Assay ◽  
Enhanced Expression ◽  
Metabolic Endotoxemia

Abstract Chronic pancreatitis (CP) is associated with elevated plasma levels of bacterial lipopolysaccharide (LPS) and we have demonstrated reduced acinar cell autophagy in human CP tissue. Therefore, we investigated the role of autophagy in experimental endotoxin-induced pancreatic injury and aimed to identify LPS in human CP tissue. Pancreatic Atg7-deficient mice were injected with a single sub-lethal dose of LPS. Expression of autophagy, apoptosis, necroptosis, and inflammatory markers was determined 3 and 24 h later utilizing immunoblotting and immunofluorescence. The presence of LPS in pancreatic tissue from mice and from patients and healthy controls was determined using immunohistochemistry, immunoblots, and chromogenic assay. Mice lacking pancreatic autophagy exhibited local signs of inflammation and were particularly sensitive to the toxic effect of LPS injection as compared to control mice. In response to LPS, Atg7Δpan mice exhibited enhanced vacuolization of pancreatic acinar cells, increase in TLR4 expression coupled to enhanced expression of NF-κΒ, JNK, and pro-inflammatory cytokines by acinar cells and enhanced infiltration by myeloid cells (but not Atg7F/F controls). Cell death was enhanced in Atg7Δpan pancreata, but only necroptosis and trypsin activation was further amplified following LPS injection along with elevated pancreatic LPS. The presence of LPS was identified in the pancreata from all 14 CP patients examined but was absent in the pancreata from all 10 normal controls. Altogether, these results support a potential role for metabolic endotoxemia in the pathogenesis of CP. Moreover, the evidence also supports the notion that autophagy plays a major cytoprotective and anti-inflammatory role in the pancreas, and blunting metabolic endotoxemia-induced CP.

Identification of the sequences controlling cyclic AMP regulation and cell-type-specific expression of a prestalk-specific gene in Dictyostelium discoideum

1987 ◽  
Vol 7 (1) ◽  
pp. 149-159
Author(s):  
S Datta ◽  
R A Firtel
Keyword(s):  
Amino Acids ◽  
Cyclic Amp ◽  
Dictyostelium Discoideum ◽  
Base Pair ◽  
Regulatory Region ◽  
Specific Gene ◽  
Cell Type ◽  
Specific Expression ◽  
Endogenous Gene ◽  
Cell Type Specific Expression

We have cloned and analyzed a developmentally and spatially regulated prestalk cell-specific gene from Dictyostelium discoideum. The gene encodes a protein highly homologous to the lysosomal cysteine proteinases cathepsin H and cathepsin B. Amino acid comparisons between these enzymes showed that the active-site amino acids were conserved, as were amino acids known to be important for catalysis and residues which form the intramolecular cysteine bridges. We have constructed a series of internal deletions, duplications, and linker scanner mutations within the region 300 base pairs 5' to the cap site. Analysis of expression of the mutations in transformants identified a approximately 35-base pair GC-rich region containing a dAdC/dGdT palindromic repeat and a G-rich box which is homologous to the 3' GT half of the palindromic repeat. Deletion or disruption of the G box resulted in a approximately 50-fold drop in the level of expression of the gene fusion in transformants in response to cyclic AMP in single-cell culture but did not affect the temporal pattern of regulation or control by cyclic AMP. The expression of such constructs during normal multicellular differentiation paralleled that of the endogenous gene; however, the level of RNA from the constructs was only approximately 10-fold lower than that of constructs containing the G box. Deletion of the 3' half of the palindromic sequence and the G box region resulted in a dramatic decrease in the level of transcription, although the constructs still showed proper temporal expression. These results suggest that this 35-base-pair region acts as an important part of the regulatory region for cell type and cyclic AMP regulation.

scholarly journals Cell-Specific Expression of Glucose-Dependent-Insulinotropic Polypeptide Is Regulated by the Transcription Factor PDX-1

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 383-391 ◽  
Author(s):  
Lisa I. Jepeal ◽  
Yoshio Fujitani ◽  
Michael O. Boylan ◽  
Cherrell N. Wilson ◽  
Christopher V. Wright ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Small Intestine ◽  
Specific Binding ◽  
Critical Role ◽  
Regulatory Region ◽  
Specific Expression ◽  
Intact Cells ◽  
K Cells ◽  
Nuclear Extracts ◽  
Specific Increase

Glucose-dependent insulinotropic polypeptide (GIP) is a potent stimulator of insulin secretion and comprises an important component of the enteroinsular axis. GIP is synthesized in enteroendocrine K-cells located principally in the upper small intestine. The homeobox-containing gene PDX-1 is also expressed in the small intestine and plays a critical role in pancreatic development and in the expression of pancreatic-specific genes. Previous studies determined that the transcription factors GATA-4 and ISL-1 are important for GIP expression. In this study, we demonstrate that PDX-1 is also involved in regulating GIP expression in K-cells. Using immunohistochemistry, we verified the expression of PDX-1 protein in the nucleus of GIP-expressing mouse K-cells and evaluated the expression of PDX-1, serotonin, and GIP in wild-type and PDX-1−/− mice at 18.5 d after conception. Although we demonstrated a 97.8% reduction in the number of GIP-expressing cells in PDX-1−/− mice; there was no statistical difference in the number of serotonin-positive cells. Additionally, PDX-1 transcripts and protein were detected in a GIP-expressing neuroendocrine cell line, STC-1. Electromobility shift assays using STC-1 nuclear extracts demonstrated the specific binding of PDX-1 protein to a specific regulatory region in the GIP promoter. Using chromatin immunoprecipitation analysis, we demonstrated binding of PDX-1 to this same region of the GIP promoter in intact cells. Lastly, overexpression of PDX-1 in transient transfection assays led to a specific increase in the activity of GIP/Luc reporter constructs. The results of these studies indicate that the transcription factor PDX-1 plays a critical role in the cell-specific expression of the GIP gene.

Electrogenic sodium pump in pancreatic acinar cells

1973 ◽  
Vol 184 (1074) ◽  
pp. 115-119 ◽  
Keyword(s):  
Cell Membrane ◽  
Acinar Cell ◽  
Sodium Pump ◽  
Acinar Cells ◽  
Pancreatic Tissue ◽  
Pancreatic Acinar Cells ◽  
Bathing Solution ◽  
Sodium Pumps ◽  
Epithelial Tissues ◽  
Electrogenic Sodium Pump

Electrogenic sodium pumps have been described in many excitable tissues, but hitherto not with certainty in epithelial tissues. In the present work it is shown that readmission of potassium to the bathing solution of mouse pancreatic tissue previously deprived of potas­sium, causes a marked hyperpolarization of the acinar cell membrane. This hyperpolariza­tion is abolished reversibly by strophanthin-G. This indicates the presence of electrogenic sodium pumping in pancreatic acinar cells.

Critical role for NHE1 in intracellular pH regulation in pancreatic acinar cells

2003 ◽  
Vol 285 (5) ◽  
pp. G804-G812 ◽  
Author(s):  
David A. Brown ◽  
James E. Melvin ◽  
David I. Yule
Keyword(s):  
Intracellular Ph ◽  
Ph Regulation ◽  
Critical Role ◽  
Acinar Cells ◽  
Pancreatic Tissue ◽  
Pancreatic Acinar Cells ◽  
Muscarinic Agonist ◽  
Targeted Disruption ◽  
General Role ◽  
Pancreatic Acini

The primary function of pancreatic acinar cells is to secrete digestive enzymes together with a NaCl-rich primary fluid which is later greatly supplemented and modified by the pancreatic duct. A Na+/H+ exchanger(s) [NHE(s)] is proposed to be integral in the process of fluid secretion both in terms of the transcellular flux of Na+ and intracellular pH (pHi) regulation. Multiple NHE isoforms have been identified in pancreatic tissue, but little is known about their individual functions in acinar cells. The Na+/H+ exchange inhibitor 5-( N-ethyl- N-isopropyl) amiloride completely blocked pHi recovery after an NH4Cl-induced acid challenge, confirming a general role for NHE in pHi regulation. The targeted disruption of the Nhe1 gene also completely abolished pHi recovery from an acid load in pancreatic acini in both [Formula: see text]-containing and [Formula: see text]-free solutions. In contrast, the disruption of either Nhe2 or Nhe3 had no effect on pHi recovery. In addition, NHE1 activity was upregulated in response to muscarinic stimulation in wild-type mice but not in NHE1-deficient mice. Fluctuations in pHi could potentially have major effects on Ca2+ signaling following secretagogue stimulation; however, the targeted disruption of Nhe1 was found to have no significant effect on intracellular Ca2+ homeostasis. These data demonstrate that NHE1 is the major regulator of pHi in both resting and muscarinic agonist-stimulated pancreatic acinar cells.

Specific expression of an elastase–human growth hormone fusion gene in pancreatic acinar cells of transgenic mice

Nature ◽  
1985 ◽  
Vol 313 (6003) ◽  
pp. 600-602 ◽  
Author(s):  
David M. Ornitz ◽  
Richard D. Palmiter ◽  
Robert E. Hammer ◽  
Ralph L. Brinster ◽  
Galvin H. Swift ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Transgenic Mice ◽  
Human Growth Hormone ◽  
Fusion Gene ◽  
Human Growth ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Specific Expression

PSD-95 protects the pancreas against pathological damage through p38 MAPK signaling pathway in acute pancreatitis

2021 ◽  
pp. 153537022110032
Author(s):  
Yinan Guo ◽  
Weikai Hu ◽  
Xueyan Wang ◽  
Chunyun Li ◽  
Tianyu Cui ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
P38 Mapk ◽  
Cell Model ◽  
Control Cell ◽  
Acinar Cells ◽  
Mapk Signaling ◽  
Pancreatic Tissue ◽  
Pancreatic Acinar Cells ◽  
Ar42j Cells ◽  
Inhibition Group

Acute pancreatitis is one of the leading causes of gastrointestinal disorder-related hospitalizations, yet its pathogenesis remains to be fully elucidated. Postsynaptic density protein-95 (PSD-95) is closely associated with tissue inflammation and injury. We aimed to investigate the expression of PSD-95 in pancreatic acinar cells, and its function in regulating the inflammatory response and pancreatic pathological damage in acute pancreatitis. A mouse model of edematous acute pancreatitis was induced with caerulein and lipopolysaccharide in C57BL/6 mice. Tat-N-dimer was injected to inhibit the PSD-95 activity separately, or simultaneously with SB203580, inhibitor of p38 MAPK phosphorylation. Rat pancreatic acinar cells AR42J were cultured with 1 μM caerulein to build a cell model of acute pancreatitis. PSD-95-knockdown and negative control cell lines were constructed by lentiviral transfection of AR42J cells. Paraffin-embedded pancreatic tissue samples were processed for routine HE staining to evaluate the pathological changes of human and mouse pancreatic tissues. Serum amylase and inflammatory cytokine levels were detected with specific ELISA kits. Immunofluorescence, immunohistochemical, Western-blot, and qRT-PCR were used to detect the expression levels of PSD-95, p38, and phosphorylated p38. Our findings showed that PSD-95 is expressed in the pancreatic tissues of humans, C57BL/6 mice, and AR42J cells, primarily in the cytoplasm. PSD-95 expression increased at 2 h, reaching the peak at 6 h in mice and 12 h in AR42J cells. IL-6, IL-8, and TNF-α increased within 2 h of disease induction. The pancreatic histopathologic score was greater in the PSD-95 inhibition group compared with the control ( P < 0.05), while it was lesser when phosphorylation of p38 MAPK was inhibited compared with the PSD-95 inhibition group ( P < 0.05). Moreover, phosphorylation of p38 MAPK increased statistically after PSD-95 knocked-down. In conclusion, PSD-95 effectively influences the pathological damage of the pancreas in acute pancreatitis by affecting the phosphorylation of p38 MAPK.

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