Versatile Retrovirus Vector Systems for Regulated Gene Expression In Vitro and In Vivo

Abstract Infection and inflammation are invariably associated with activation of the blood coagulation mechanism, secondary to the inflammation-induced expression of the coagulation initiator tissue factor (TF) on innate immune cells. By investigating the role of cell-surface receptors for coagulation factors in mouse endotoxemia, we found that the protein C receptor (ProcR; EPCR) was required for the normal in vivo and in vitro induction of lipopolysaccharide (LPS)-regulated gene expression. In cultured bone marrow–derived myeloid cells and in monocytic RAW264.7 cells, the LPS-induced expression of functionally active TF, assembly of the ternary TF-VIIa-Xa initiation complex of blood coagulation, and the EPCR-dependent activation of protease-activated receptor 2 (PAR2) by the ternary TF-VIIa-Xa complex were required for the normal LPS induction of messenger RNAs encoding the TLR3/4 signaling adaptor protein Pellino-1 and the transcription factor interferon regulatory factor 8. In response to in vivo challenge with LPS, mice lacking EPCR or PAR2 failed to fully initiate an interferon-regulated gene expression program that included the Irf8 target genes Lif, Iigp1, Gbp2, Gbp3, and Gbp6. The inflammation-induced expression of TF and crosstalk with EPCR, PAR2, and TLR4 therefore appear necessary for the normal evolution of interferon-regulated host responses.

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Cardiac transgenesis with the tetracycline transactivator changes myocardial function and gene expression

Physiological Genomics ◽

10.1152/physiolgenomics.00016.2005 ◽

2005 ◽

Vol 22 (1) ◽

pp. 118-126 ◽

Cited By ~ 26

Author(s):

Diana T. McCloskey ◽

Lynne Turnbull ◽

Philip M. Swigart ◽

Alexander C. Zambon ◽

Sally Turcato ◽

...

Keyword(s):

Gene Expression ◽

Transgenic Mice ◽

Target Gene ◽

Control Group ◽

Transcription Activator ◽

Tet System ◽

Double Transgenic Mice ◽

Regulated Gene Expression

The cardiac-specific tetracycline-regulated gene expression system (tet-system) is a powerful tool using double-transgenic mice. The cardiac α-myosin heavy chain promoter (αMHC) drives lifetime expression of a tetracycline-inhibited transcription activator (tTA). Crossing αMHC-tTA mice with mice containing a tTA-responsive promoter linked to a target gene yields double-transgenic mice having tetracycline-repressed expression of the target gene in the heart. Using the tet-system, some studies use nontransgenic mice for the control group, whereas others use single-transgenic αMHC-tTA mice. However, previous studies found that high-level expression of a modified activator protein caused cardiomyopathy. Therefore, we tested whether cardiac expression of tTA was associated with altered function of αMHC-tTA mice compared with wild-type (WT) littermates. We monitored in vivo and in vitro function and gene expression profiles for myocardium from WT and αMHC-tTA mice. Compared with WT littermates, αMHC-tTA mice had a greater heart-to-body weight ratio (≈10%), ventricular dilation, and decreased ejection fraction, suggesting mild cardiomyopathy. In vitro, submaximal contractions were greater compared with WT and were associated with greater myofilament Ca2+ sensitivity. Gene expression profiling revealed that the expression of 153 genes was significantly changed by >20% when comparing αMHC-tTA with WT myocardium. These findings demonstrate that introduction of the αMHC-tTA construct causes significant effects on myocardial gene expression and major functional abnormalities in vivo and in vitro. For studies using the tet-system, these results suggest caution in the use of controls, since αMHC-tTA myocardium differs appreciably from WT. Furthermore, the results raise the possibility that the phenotype conferred by a target gene may be influenced by the modified genetic background of αMHC-tTA myocardium.

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Novel Transcriptional Regulatory Signals in the Adeno-Associated Virus Terminal Repeat A/D Junction Element

Journal of Virology ◽

10.1128/jvi.74.18.8732-8739.2000 ◽

2000 ◽

Vol 74 (18) ◽

pp. 8732-8739 ◽

Cited By ~ 81

Author(s):

Rebecca P. Haberman ◽

Thomas J. McCown ◽

Richard Jude Samulski

Keyword(s):

Gene Expression ◽

Fluorescent Protein ◽

Terminal Repeat ◽

Cmv Promoter ◽

Adeno Associated Virus ◽

Regulated Expression ◽

Regulated Gene Expression

ABSTRACT Adeno-associated virus (AAV) type 2 vectors transfer stable, long-term gene expression to diverse cell types in vivo. Many gene therapy applications require the control of long-term transgene expression, and AAV vectors, similar to other gene transfer systems, are being evaluated for delivery of regulated gene expression cassettes. Previously, we (R. P. Haberman, T. J. McCown, and R. J. Samulski, Gene Ther. 5:1604–1611, 1998) demonstrated the use of the tetracycline-responsive system for long-term regulated expression in rat brains. In that study, we also observed residual expression in the “off” state both in vitro and in vivo, suggesting that the human cytomegalovirus (CMV) major immediate-early minimal promoter or other cis-acting elements (AAV terminal repeats [TR]) were contributing to this activity. In the present study, we identify that the AAV TR, minus the tetracycline-responsive minimal CMV promoter, will initiate mRNA expression from vector templates. Using deletion analysis and specific PCR-derived TR reporter gene templates, we mapped this activity to a 37-nucleotide stretch in theA/D elements of the TR. Although the mRNA derived from the TR is generated from a non-TATA box element, the use of mutant templates failed to identify function of canonical initiator sequences as previously described. Finally, we demonstrated the presence of green fluorescent protein expression both in vitro and in vivo in brain by using recombinant virus carrying only the TR element. Since the AAV terminal repeat is a necessary component of all recombinant AAV vectors, this TR transcriptional activity may interfere with all regulated expression cassettes and may be a problem in the development of novel TR split gene vectors currently being considered for genes too large to be packaged.

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Virulence gene regulation inside and outside

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2000.0606 ◽

2000 ◽

Vol 355 (1397) ◽

pp. 657-665 ◽

Cited By ~ 14

Author(s):

Victor J. DiRita ◽

N. Cary Engleberg ◽

Andrew Heath ◽

Alita Miller ◽

J. Adam Crawford ◽

...

Keyword(s):

Gene Expression ◽

Gene Regulation ◽

Regulatory System ◽

Virulence Gene ◽

Virulence Gene Expression ◽

Regulatory Cascade ◽

Transcription Activators ◽

Regulated Gene Expression

Much knowledge about microbial gene regulation and virulence is derived from genetic and biochemical studies done outside of hosts. The aim of this review is to correlate observations made in vitro and in vivo with two different bacterial pathogens in which the nature of regulated gene expression leading to virulence is quite different. The first is Vibrio cholerae , in which the concerted action of a complicated regulatory cascade involving several transcription activators leads ultimately to expression of cholera toxin and the toxin–coregulated pilus. The regulatory cascade is active in vivo and is also required for maintenance of V . cholerae in the intestinal tract during experimental infection. Nevertheless, specific signals predicted to be generated in vivo , such as bile and a temperature of 37°C, have a severe downmodulating effect on activation of toxin and pilus expression. Another unusual aspect of gene regulation in this system is the role played by inner membrane proteins that activate transcription. Although the topology of these proteins suggests an appealing model for signal transduction leading to virulence gene expression, experimental evidence suggests that such a model may be simplistic. In Streptococcus pyogenes , capsule production is critical for virulence in an animal model of necrotizing skin infection. Yet capsule is apparently produced to high levels only from mutation in a two–component regulatory system, CsrR and CsrS. Thus it seems that in V . cholerae a complex regulatory pathway has evolved to control virulence by induction of gene expression in vivo , whereas in S. pyogenes at least one mode of pathogenicity is potentiated by the absence of regulation.

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Identification of genes early responsive to gamma-irradiation in isolated rat hepatocytes in vitro and rat liver in vivo by cDNA array gene expression analysis

Zeitschrift für Gastroenterologie ◽

10.1055/s-2005-920060 ◽

2005 ◽

Vol 43 (05) ◽

Author(s):

DS Batusic ◽

H Christiansen ◽

B Saile ◽

RM Hermann ◽

J Dudas ◽

...

Keyword(s):

Gene Expression ◽

Gamma Irradiation ◽

Rat Liver ◽

Gene Expression Analysis ◽

Cdna Array ◽

Rat Hepatocytes ◽

Isolated Rat Hepatocytes ◽

Isolated Rat

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Effect of X-irradiation on gene expression of rat liver chemokines: in vivo and in vitro studies

Zeitschrift für Gastroenterologie ◽

10.1055/s-2008-1037499 ◽

2008 ◽

Vol 46 (01) ◽

Cited By ~ 1

Author(s):

F Moriconi ◽

H Christiansen ◽

N Sheikh ◽

J Dudas ◽

...

Keyword(s):

Gene Expression ◽

Rat Liver ◽

In Vitro Studies ◽

X Irradiation

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Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

Diseases of Aquatic Organisms ◽

10.3354/dao03475 ◽

2020 ◽

Vol 139 ◽

pp. 153-160

Author(s):

S Peeralil ◽

TC Joseph ◽

V Murugadas ◽

PG Akhilnath ◽

VN Sreejith ◽

...

Keyword(s):

Gene Expression ◽

Virulence Genes ◽

Vibrio Harveyi ◽

Penaeus Monodon ◽

Challenge Test ◽

Virulence Gene ◽

Economic Losses ◽

Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

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