Insulin response of a hybrid amylase/CAT gene in transgenic mice.

The alpha B-crystallin gene is expressed at high levels in lens and at lower levels in some other tissues, notably skeletal and cardiac muscle, kidney, lung, and brain. A promoter fragment of the murine alpha B-crystallin gene extending from positions -661 to +44 and linked to the bacterial chloramphenicol acetyltransferase (CAT) gene showed preferential expression in lens and skeletal muscle in transgenic mice. Transfection experiments revealed that a region between positions -426 and -257 is absolutely required for expression in C2C12 and G8 myotubes, while sequences downstream from position -115 appear to be determinants for lens expression. In association with a heterologous promoter, a -427 to -259 fragment functions as a strong enhancer in C2C12 myotubes and less efficiently in myoblasts and lens. Gel shift and methylation interference studies demonstrated that nuclear proteins from C2C12 myoblasts and myotubes specifically bind to the enhancer.

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Dietary regulation of pancreatic amylase in transgenic mice mediated by a 126-base pair DNA fragment

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1992.262.6.g971 ◽

1992 ◽

Vol 262 (6) ◽

pp. G971-G976 ◽

Cited By ~ 1

Author(s):

R. M. Schmid ◽

M. H. Meisler

Keyword(s):

Transgenic Mice ◽

Base Pair ◽

Insulin Response ◽

Regulatory Elements ◽

Regulatory Sequences ◽

Pancreatic Amylase ◽

Amylase Gene ◽

Dietary Regulation ◽

Dna Fragment ◽

Responsive Element

Expression of the mouse pancreatic amylase gene Amy-2.2 is increased approximately 10-fold in response to increasing the carbohydrate content of the diet from 9.6 to 74%. The DNA sequence mediating this response has been localized to the 5' flanking region of the amylase gene by analysis of hybrid constructs in transgenic mice. The results define a 127-base pair dietary response unit that includes two previously described regulatory elements, an insulin-responsive element and a pancreatic enhancer. Fragments containing these two elements alone fail to respond to diet, demonstrating a requirement for additional regulatory sequences. Another mouse amylase gene Amy-2.1 is only minimally responsive to insulin and to diet. The data are consistent with the hypothesis that the insulin-response element is necessary but not sufficient for regulation of amylase by dietary carbohydrate.

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TFE3 Controls Lipid Metabolism in Adipose Tissue of Male Mice by Suppressing Lipolysis and Thermogenesis

Endocrinology ◽

10.1210/en.2013-1203 ◽

2013 ◽

Vol 154 (10) ◽

pp. 3577-3588 ◽

Cited By ~ 21

Author(s):

Yuri Fujimoto ◽

Yoshimi Nakagawa ◽

Aoi Satoh ◽

Kanako Okuda ◽

Akiko Shingyouchi ◽

...

Keyword(s):

Transcription Factor ◽

Adipose Tissue ◽

Lipid Metabolism ◽

Transgenic Mice ◽

Brown Adipose Tissue ◽

Lipase Activity ◽

Mrna Level ◽

Insulin Response ◽

Brown Adipose ◽

New Evidence

Transcription factor E3 (TFE3) is a transcription factor that binds to E-box motifs and promotes energy metabolism-related genes. We previously reported that TFE3 directly binds to the insulin receptor substrate-2 promoter in the liver, resulting in increased insulin response. However, the role of TFE3 in other tissues remains unclear. In this study, we generated adipose-specific TFE3 transgenic (aP2-TFE3 Tg) mice. These mice had a higher weight of white adipose tissue (WAT) and brown adipose tissue than wild-type (WT) mice under fasting conditions. Lipase activity in the WAT in these mice was lower than that in the WT mice. The mRNA level of adipose triglyceride lipase (ATGL), the rate-limiting enzyme for adipocyte lipolysis, was significantly decreased in aP2-TFE3 Tg mice. The expression of Foxo1, which directly activates ATGL expression, was also suppressed in transgenic mice. Promoter analysis confirmed that TFE3 suppressed promoter activities of the ATGL gene. In contrast, G0S2 and Perilipin1, which attenuate ATGL activity, were higher in transgenic mice than in WT mice. These results indicated that the decrease in lipase activity in adipose tissues was due to a decrease in ATGL expression and suppression of ATGL activity. We also showed that thermogenesis was suppressed in aP2-TFE3 Tg mice. The decrease in lipolysis in WAT of aP2-TFE3 Tg mice inhibited the supply of fatty acids to brown adipose tissue, resulting in the inhibition of the expression of thermogenesis-related genes such as UCP1. Our data provide new evidence that TFE3 regulates lipid metabolism by controlling the gene expression related to lipolysis and thermogenesis in adipose tissue.

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Human apolipoprotein D overexpression in transgenic mice induces insulin resistance and alters lipid metabolism

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.90725.2008 ◽

2009 ◽

Vol 296 (4) ◽

pp. E802-E811 ◽

Cited By ~ 19

Author(s):

Sonia Do Carmo ◽

David Fournier ◽

Catherine Mounier ◽

Eric Rassart

Keyword(s):

Insulin Resistance ◽

Transgenic Mice ◽

Insulin Response ◽

Lipid Concentration ◽

Insulin Resistant ◽

Human Apolipoprotein ◽

Metabolic Defects ◽

Impaired Insulin ◽

Apolipoprotein D ◽

Small Hydrophobic

Apolipoprotein D (apoD), a widely expressed lipocalin, has the capacity to transport small hydrophobic molecules. Although it has been proposed that apoD may have multiple tissue-specific, physiological ligands and functions, these have yet to be identified. To gain insight in some of its functions, we generated transgenic mice overexpressing human apoD (H-apoD) under the control of neuron-specific promoters. In Thy-1/apoD and NSE/apoD mice, expression of H-apoD was strong in the nervous system although weakly detected in peripheral organs such as the liver and blood cells. These mice displayed not entirely anticipated metabolic defects. Although they are not obese and have normal lipid concentration in circulation, Thy-1/apoD and NSE/apoD mice are glucose intolerant, insulin resistant, and develop hepatic steatosis. The steatosis and its associated insulin resistance are correlated with impairments in hepatic lipogenesis. However, they are not strongly related with inflammation. This impaired insulin response is not caused by a decrease in circulating leptin or a modulation of adiponectin and resistin levels. These results suggest that variations in the levels and/or sites of apoD expression influence the lipid and glucose metabolism, consolidating apoD as a target for insulin-resistance-related disorders.

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Disturbedα-Cell Function in Mice withβ-Cell Specific Overexpression of Human Islet Amyloid Polypeptide

Experimental Diabetes Research ◽

10.1155/2008/304513 ◽

2008 ◽

Vol 2008 ◽

pp. 1-4 ◽

Cited By ~ 5

Author(s):

Bo Ahrén ◽

Maria Sörhede Winzell

Keyword(s):

Gastric Emptying ◽

Transgenic Mice ◽

Cell Function ◽

Islet Amyloid Polypeptide ◽

Insulin Response ◽

Glucagon Secretion ◽

Transgenic Animals ◽

Inhibitory Influence ◽

Islet Amyloid ◽

Glucose Levels

Exogenous administration of islet amyloid polypeptide (IAPP) has been shown to inhibit both insulin and glucagon secretion. This study examinedα-cell function in mice withβ-cell specific overexpression of human IAPP (hIAPP) after an oral protein gavage (75 mg whey protein/mouse). Baseline glucagon levels were higher in transgenic mice (41±4.0 pg/mL,n=6) than in wildtype animals (19±5.1 pg/mL,n=5,P=.015). In contrast, the glucagon response to protein was impaired in transgenic animals (21±2.7 pg/mL in transgenic mice versus 38±5.7 pg/mL in wildtype mice at 15 minutes;P=.027). Baseline insulin levels did not differ between the groups, while the insulin response, as the glucagon response, was impaired after protein challenge (P=.018). Glucose levels were not different between the groups and did not change significantly after protein gavage. Acetaminophen was given through gavage to the animals (2 mg/mouse) to estimate gastric emptying. The plasma acetaminophen profile was similar in the two groups of mice. We conclude that disturbances in glucagon secretion exist in mice withβ-cell specific overexpression of human IAPP, which are not secondary to changes in gastric emptying. The reduced glucagon response to protein challenge may reflect a direct inhibitory influence of hIAPP on glucagon secretion.

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Genetic element from human surfactant protein SP-C gene confers bronchiolar-alveolar cell specificity in transgenic mice

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1991.261.4.l349 ◽

1991 ◽

Vol 261 (4) ◽

pp. L349-L356 ◽

Cited By ~ 26

Author(s):

S. W. Glasser ◽

T. R. Korfhagen ◽

S. E. Wert ◽

M. D. Bruno ◽

K. M. McWilliams ◽

...

Keyword(s):

In Situ Hybridization ◽

Transgenic Mice ◽

Transgenic Mouse ◽

Fetal Lung ◽

Surfactant Protein ◽

Developmental Expression ◽

Chimeric Genes ◽

Cat Gene ◽

Mouse Lines

Transgenic mice bearing chimeric genes consisting of 5'-sequences derived from the human surfactant protein C (SP-C) gene and the bacterial chloramphenicol acetyltransferase (CAT) gene were generated. Analysis of CAT activity was utilized to demonstrate tissue-specific and developmental expression of chimeric genes containing 3.7 kb of sequences from the human SP-C gene. Lung-specific expression of the 3.7 SP-C-CAT transgene was observed in eight distinct transgenic mouse lines. Expression of the 3.7 SP-C-CAT transgene was first detected in fetal lung on day 11 of gestation and increased dramatically with advancing gestational age, reaching adult levels of activity before birth. In situ hybridization demonstrated that expression of 3.7 SP-C-CAT mRNA was confined to the distal respiratory epithelium. Antisense CAT hybridization was detected in bronchiolar and type II epithelial cells in the adult lung of the 3.7 SP-C-CAT transgenic mice. In situ hybridization of four distinct 3.7 SP-C-CAT transgenic mouse lines demonstrated bronchiolar-alveolar expression of the chimeric CAT gene, although the relative intensity of expression at each site varied within the lines studied. Glucocorticoids increased murine SP-C mRNA in fetal lung organ culture. Likewise, expression of 3.7 SP-C-CAT transgene increased during fetal lung organ or explant culture and was further enhanced by glucocorticoid in vitro. The 5'-regions of human SP-C conferred developmental, lung epithelial, and glucocorticoid-enhanced expression of bacterial CAT in transgenic mice. The increased expression of SP-C accompanying prenatal lung development and exposure to glucocorticoid is mediated, at least in part, at the transcriptional level, being influenced by cis-active elements contained within the 5'-flanking region of the human SP-C gene.

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Mouse testis Pdha-2 promoter upstream sequences confer tissue-and temporal-specific activity in transgenic mice

Reproduction Fertility and Development ◽

10.1071/rd9940599 ◽

1994 ◽

Vol 6 (5) ◽

pp. 599 ◽

Cited By ~ 4

Author(s):

RC Iannello ◽

JC Young ◽

S Sumarsono ◽

MJ Tymms ◽

I Kola

Keyword(s):

Transgenic Mice ◽

Specific Activity ◽

Pyruvate Dehydrogenase Complex ◽

Somatic Tissue ◽

Specific Expression ◽

Complex Process ◽

Specific Manner ◽

Cat Gene ◽

Testis Specific Expression

Spermatogenesis is a complex process requiring the coordinate expression of a number of testis-specific genes. One of these, Pdha-2, codes for the murine testis-specific isoform of the E1 alpha subunit of the pyruvate dehydrogenase complex. To elucidate the mechanisms regulating its expression in vivo, we have begun to investigate the Pdha-2 promoter in transgenic mice. In this paper, a construct containing 3.0 kb of promoter and upstream sequences is reported to be sufficient for directing the testis-specific expression of a CAT reporter gene in mice harbouring the transgene. Similarly to the endogenous Pdha-2, the CAT gene is expressed in testis in a stage-specific manner. However, the 3.0-kb Pdha-2 promoter is not active in somatic tissue suggesting that repressor elements may be present within these sequences.

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