scholarly journals The use of human CD68 transcriptional regulatory sequences to direct high-level expression of class A scavenger receptor in macrophages in vitro and in vivo

Immunology ◽  
2001 ◽  
Vol 103 (3) ◽  
pp. 351-361 ◽  
Author(s):  
Peter J. Gough ◽  
Siamon Gordon ◽  
David R. Greaves
Keyword(s):  
Scavenger Receptor ◽  
Regulatory Sequences ◽  
High Level Expression ◽  
Class A ◽  
Transcriptional Regulatory ◽  
High Level ◽  
Class A Scavenger Receptor

scholarly journals Thyroid hormone induces constitutive keratin gene expression during Xenopus laevis development.

1989 ◽  
Vol 9 (5) ◽  
pp. 1823-1831 ◽  
Author(s):  
P M Mathisen ◽  
L Miller
Keyword(s):  
Thyroid Hormone ◽  
Xenopus Laevis ◽  
Constitutive Expression ◽  
High Level Expression ◽  
Keratin Gene ◽  
Explant Cultures ◽  
Extensive Cell ◽  
High Level

We have used in vitro explant cultures of Xenopus laevis skin to investigate the role that the thyroid hormone triiodothyronine (T3) plays in activating the 63-kilodalton (kDa) keratin genes. The activation of these genes in vivo requires two distinct steps, one independent of T3 and one dependent on T3. In this report we have shown that the same two steps are required to fully activate the 63-kDa keratin genes in skin explant cultures, and we have characterized the T3-mediated step in greater detail. Unlike the induction of transcription by T3 or steroid hormones in adult tissues, there was a long latent period of approximately 2 days between the addition of T3 to skin cultures and an increase in concentration of keratin mRNA. While the T3 induction of 63-kDa keratin gene transcription cannot occur until age 48, a short transient exposure of stage 40 skin cultures to T3 resulted in high-level expression of these genes 5 days later, when normal siblings had reached stage 48. This result indicates that T3 induces a stable change in epidermal cells which can be expressed much later, after extensive cell proliferation has occurred in the absence of T3. Once the 63-kDa keratin genes were induced, they were stably expressed, and by the end of metamorphosis T3 had no further effect on their expression. The results suggest that T3 induces constitutive expression of the 63-kDa keratin genes during metamorphosis.

scholarly journals Cross-Competition in Transgenic Chloroplasts Expressing Single Editing Sites Reveals Shared cis Elements

2002 ◽  
Vol 22 (24) ◽  
pp. 8448-8456 ◽  
Author(s):  
Anne-Laure Chateigner-Boutin ◽  
Maureen R. Hanson
Keyword(s):  
Editing Site ◽  
Competition Effect ◽  
High Level Expression ◽  
Consensus Sequences ◽  
Endogenous Genes ◽  
High Level ◽  
Cross Competition ◽  
Selection Of

ABSTRACT RNA editing in organelles of angiosperm plants results in alteration of Cs to Us in transcripts. In most editing sites analyzed in vitro or in vivo, sequences within approximately 30 nucleotides (nt) 5′ and 10 nt 3′ of the edited C have been found to be required for selection of the correct C editing target and for editing efficiency, but no consensus sequences have been identified. The effect of high-level expression of two different minigenes carrying either the rpoB-2 or the ndhF-2 editing site on editing was determined for all 31 known edited Cs in two transgenic tobacco lines. The editing efficiencies of both the corresponding rpoB and ndhF editing sites in the endogenous genes' transcripts and in several other genes' transcripts were reduced in the chloroplast transgenic plants. Conserved nucleotides could be identified in the sequences immediately 5′ of each overexpressed editing site and in the sites in the additional genes that experienced a competition effect, though the conserved nucleotides differ 5′ of rpoB-2 and 5′ of ndhF-2. Inspection of sequences surrounding chloroplast and mitochondrial editing sites reveals that they can be grouped into clusters which carry conserved nucleotides within 30 nt 5′ of the C target of editing. The data are consistent with a model in which the same trans factor recognizes several chloroplast or mitochondrial editing sites, depending on the particular sequence 5′ of the edited C.

scholarly journals AZF1 Is a Glucose-Dependent Positive Regulator of CLN3 Transcription in Saccharomyces cerevisiae

2002 ◽  
Vol 22 (5) ◽  
pp. 1607-1614 ◽  
Author(s):  
Laura L. Newcomb ◽  
Duane D. Hall ◽  
Warren Heideman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Zinc Finger Protein ◽  
Regulatory Protein ◽  
Hybrid Approach ◽  
Regulatory Sequences ◽  
Positive Role ◽  
Transcriptional Regulatory ◽  
Dna Elements

ABSTRACT Transcription of the CLN3 G1 cyclin in Saccharomyces cerevisiae is positively regulated by glucose in a process that involves a set of DNA elements with the sequence AAGAAAAA (A2GA5). To identify proteins that interact with these elements, we used a 1-hybrid approach, which yielded a nuclear zinc finger protein previously identified as Azf1. Gel shift and chromatin immunoprecipitation experiments show that Azf1 binds to the A2GA5 CLN3 regulatory sequences in vitro and in vivo, thus identifying a transcriptional regulatory protein for CLN3 and a DNA sequence target for Azf1. We show that glucose-induced expression of a reporter gene driven by the A2GA5 CLN3 regulatory sequences is dependent upon the presence of AZF1. Furthermore, deletion of AZF1 markedly reduces the transcriptional induction of CLN3 by glucose. In addition, Azf1 can induce reporter expression in a glucose-specific manner when artificially tethered to a promoter via the DNA-binding domain from Gal4. We conclude that AZF1 is a glucose-dependent transcription factor that interacts with the CLN3 A2GA5 repeats to play a positive role in the regulation of CLN3 mRNA expression by glucose.

scholarly journals Defining the Regulatory Factors Required for Epidermal Gene Expression

2000 ◽  
Vol 20 (7) ◽  
pp. 2543-2555 ◽  
Author(s):  
Satrajit Sinha ◽  
Linda Degenstein ◽  
Cedith Copenhaver ◽  
Elaine Fuchs
Keyword(s):  
Transgenic Mice ◽  
Specific Activity ◽  
Regulatory Sequences ◽  
Mobility Shift ◽  
Heterologous Promoter ◽  
Hypersensitive Sites ◽  
Dna Fragment ◽  
High Level

ABSTRACT Keratins K5 and K14 are the hallmarks of mitotically active keratinocytes of stratified epithelia. They are transcribed at a high level and in a tissue-specific manner, enabling us to use the K14 gene to elucidate the regulatory mechanism underlying epidermis-specific transcription. We have identified four DNase I-hypersensitive sites (HSs) present in the 5′ regulatory sequences of the K14 gene under specific conditions where the gene is actively expressed. Two of these sites (HSsII and -III) are conserved in position and sequence within the human and mouse K14 genes. Using an in vivo transgenic approach and an in vitro keratinocyte culture approach, we have discovered that most of K14's transcriptional activity is restricted to a novel 700-bp regulatory domain encompassing these HSs. This enhancer is sufficient to confer epidermis-specific activity to a heterologous promoter in transfection assays in culture and in transgenic mice in vivo. A 125-bp DNA fragment encompassing HSsII harbors the majority of the transactivation activity in vitro, and electrophoretic mobility shift and mutational assays reveal a role for AP-1, ets, and AP-2 family members in orchestrating the keratinocyte-preferred expression of HSsII. The HSsII element also confers epidermal expressivity to a heterologous promoter in transgenic mice, although it is not sufficient on its own to fully restrict activity to keratinocytes. Within the HSsII element, the ets and AP-2 sites appear to be most critical in collaborating to regulate epidermal specificity in vivo.

Scavenger receptor class A type I/II (CD204) null mice fail to develop fibrosis following silica exposure

2005 ◽  
Vol 289 (2) ◽  
pp. L186-L195 ◽  
Author(s):  
Celine A. Beamer ◽  
Andrij Holian
Keyword(s):  
Scavenger Receptor ◽  
Lavage Fluid ◽  
Type I ◽  
Dependent Manner ◽  
Wild Type ◽  
Focal Lesions ◽  
Silica Exposure ◽  
Class A

Alveolar macrophages express the class A scavenger receptor (CD204) (Babaev VR, Gleaves LA, Carter KJ, Suzuki H, Kodama T, Fazio S, and Linton MF. Arterioscler Thromb Vasc Biol 20: 2593–2599, 2000); yet its role in vivo in lung defense against environmental particles has not been clearly defined. In the current study, CD204 null mice (129Sv background) were used to investigate the link between CD204 and downstream events of inflammation and fibrosis following silica exposure in vivo. CD204−/− macrophages were shown to recognize and uptake silica in vitro, although this response was attenuated compared with 129Sv wild-type mice. The production of tumor necrosis factor-α in lavage fluid was significantly enhanced in CD204 null mice compared with wild-type mice following silica exposure. Moreover, after exposure to environmental particles, CD204−/− macrophages exhibited improved cell viability in a dose-dependent manner compared with wild-type macrophages. Finally, histopathology from a murine model of chronic silicosis in 129Sv wild-type mice displayed typical focal lesions, interstitial thickening with increased connective tissue matrix, and cellular infiltrate into air space. In contrast, CD204−/− mice exhibited little to no deposition of collagen, yet they demonstrated enhanced accumulation of inflammatory cells largely composed of neutrophils. Our findings point to an important role of CD204 in mounting an efficient and appropriately regulated immune response against inhaled particles. Furthermore, these results indicate that the functions of CD204 are critical to the development of fibrosis and the resolution of inflammation.

Thyroid hormone induces constitutive keratin gene expression during Xenopus laevis development

1989 ◽  
Vol 9 (5) ◽  
pp. 1823-1831
Author(s):  
P M Mathisen ◽  
L Miller
Keyword(s):  
Thyroid Hormone ◽  
Xenopus Laevis ◽  
Constitutive Expression ◽  
High Level Expression ◽  
Keratin Gene ◽  
Explant Cultures ◽  
Extensive Cell ◽  
High Level

We have used in vitro explant cultures of Xenopus laevis skin to investigate the role that the thyroid hormone triiodothyronine (T3) plays in activating the 63-kilodalton (kDa) keratin genes. The activation of these genes in vivo requires two distinct steps, one independent of T3 and one dependent on T3. In this report we have shown that the same two steps are required to fully activate the 63-kDa keratin genes in skin explant cultures, and we have characterized the T3-mediated step in greater detail. Unlike the induction of transcription by T3 or steroid hormones in adult tissues, there was a long latent period of approximately 2 days between the addition of T3 to skin cultures and an increase in concentration of keratin mRNA. While the T3 induction of 63-kDa keratin gene transcription cannot occur until age 48, a short transient exposure of stage 40 skin cultures to T3 resulted in high-level expression of these genes 5 days later, when normal siblings had reached stage 48. This result indicates that T3 induces a stable change in epidermal cells which can be expressed much later, after extensive cell proliferation has occurred in the absence of T3. Once the 63-kDa keratin genes were induced, they were stably expressed, and by the end of metamorphosis T3 had no further effect on their expression. The results suggest that T3 induces constitutive expression of the 63-kDa keratin genes during metamorphosis.

scholarly journals Constitutive High Expression of Chromosomal β-Lactamase in Pseudomonas aeruginosa Caused by a New Insertion Sequence (IS1669) Located in ampD

2002 ◽  
Vol 46 (11) ◽  
pp. 3406-3411 ◽  
Author(s):  
Niels Bagge ◽  
Oana Ciofu ◽  
Morten Hentzer ◽  
Joan I. A. Campbell ◽  
Michael Givskov ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Insertion Sequence ◽  
Enterobacter Cloacae ◽  
High Level Expression ◽  
Dramatic Decrease ◽  
Strain Pao1 ◽  
Genetic Changes ◽  
High Level

ABSTRACT The expression of chromosomal AmpC β-lactamase in Pseudomonas aeruginosa is negatively regulated by the activity of an amidase, AmpD. In the present study we examined resistant clinical P. aeruginosa strains and several resistant variants isolated from in vivo and in vitro biofilms for mutations in ampD to find evidence for the genetic changes leading to high-level expression of chromosomal β-lactamase. A new insertion sequence, IS1669, was found located in the ampD genes of two clinical P. aeruginosa isolates and several biofilm-isolated variants. The presence of IS1669 in ampD resulted in the expression of high levels of AmpC β-lactamase. Complementation of these isolates with ampD from the reference P. aeruginosa strain PAO1 caused a dramatic decrease in the expression of AmpC β-lactamase and a parallel decrease of the MIC of ceftazidime to a level comparable to that of PAO1. One highly resistant, constitutive β-lactamase-producing variant contained no mutations in ampD, but a point mutation was observed in ampR, resulting in an Asp-135→Asn change. An identical mutation of AmpR in Enterobacter cloacae has been reported to cause a 450-fold higher AmpC expression. However, in many of the isolates expressing high levels of chromosomal β-lactamase, no changes were found in either ampD, ampR, or in the promoter region of ampD, ampR, or ampC. Our results suggest that multiple pathways may exist leading to increased antimicrobial resistance due to chromosomal β-lactamase.

scholarly journals Stable High-Level Expression of Heterologous Genes In Vitro and In Vivo by Noncytopathic DNA-Based Kunjin Virus Replicon Vectors

2000 ◽  
Vol 74 (9) ◽  
pp. 4394-4403 ◽  
Author(s):  
Andrei N. Varnavski ◽  
Paul R. Young ◽  
Alexander A. Khromykh
Keyword(s):  
Host Cells ◽  
Mouse Lung ◽  
Lung Epithelium ◽  
High Level Expression ◽  
Mammalian Cell Lines ◽  
Rna Transfection ◽  
Intramuscular Inoculation ◽  
High Level

ABSTRACT Primary features of the flavivirus Kunjin (KUN) subgenomic replicons include continuous noncytopathic replication in host cell cytoplasm and the ability to be encapsidated into secreted virus-like particles (VLPs). Previously we reported preparation of RNA-based KUN replicon vectors and expression of heterologous genes (HG) in cell culture after RNA transfection or after infection with recombinant KUN VLPs (A. N. Varnavski and A. A. Khromykh, Virology 255:366–375, 1999). In this study we describe the development of the next generation of KUN replicon vectors, which allow synthesis of replicon RNA in vivo from corresponding plasmid DNAs. These DNA-based vectors were able to direct stable expression of β-galactosidase (β-Gal) in several mammalian cell lines, and expression remained high (∼150 pg per cell) throughout cell passaging. The applicability of these vectors in vivo was demonstrated by β-Gal expression in the mouse lung epithelium for at least 8 weeks after intranasal inoculation and induction of anti-β-Gal antibody response after intramuscular inoculation of the β-Gal-encoding KUN replicon DNA. The noncytopathic nature of DNA-based KUN replicon vectors combined with high-level and stability of HG expression in a broad range of host cells should prove them to be useful in a variety of applications in vitro and in vivo.

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