scholarly journals Hypoxia-directed tumor targeting of CRISPR/Cas9 and HSV-TK suicide gene therapy using lipid nanoparticles

2021 ◽  
Author(s):  
Alicia Davis ◽  
Kevin V. Morris ◽  
Galina Shevchenko
Keyword(s):  
Gene Expression ◽  
Tumor Cells ◽  
Target Genes ◽  
High Efficiency ◽  
Hypoxia Inducible Factor ◽  
Suicide Gene ◽  
Lipid Nanoparticles ◽  
Specific Gene ◽  
Specific Expression ◽  
Specific Gene Expression

AbstractHypoxia is a characteristic feature of solid tumors that contributes to tumor aggressiveness and is associated with resistance to cancer therapy. The hypoxia inducible factor-1 (HIF-1) transcription factor complex mediates hypoxia-specific gene expression by binding to hypoxia responsive element (HRE) sequences within the promoter of target genes. HRE driven expression of therapeutic cargo has been widely explored as a strategy to achieve cancer-specific gene expression. By utilizing this system, we achieve hypoxia-specific expression of two therapeutically relevant cargo elements: the Herpes Simplex Virus thymidine kinase (HSV-tk) suicide gene and the CRISPR/Cas9 nuclease. Using an expression vector containing five copies of the HRE derived from the vascular endothelial growth factor gene, we are able to show high transgene expression in cells in a hypoxic environment, similar to levels achieved using the CMV and CBh promoters. Furthermore, we are able to deliver our therapeutic cargo to tumor cells with high efficiency using plasmid packaged lipid nanoparticles (LNPs) to achieve specific killing of tumor cells in hypoxic conditions, while maintaining tight regulation with no significant changes to cell viability in normoxia.

Stage-specific expression of a developmentally regulated gene in Dirofilaria immitis

1992 ◽  
Vol 66 (1) ◽  
pp. 62-67 ◽  
Author(s):  
S. Sun ◽  
T. Matsuura ◽  
K. Sugane
Keyword(s):  
Gene Expression ◽  
Cdna Clone ◽  
Dirofilaria Immitis ◽  
Mrna Level ◽  
Specific Antigen ◽  
Specific Gene ◽  
Developmentally Regulated ◽  
Specific Expression ◽  
Specific Gene Expression

ABSTRACTA previously reported cDNA clone encoding 34 kDa antigenic polypeptide of Dirofilaria immitis (λ cD34) was studied to elucidate the mechanism of stage-specific gene expression. The 34 kDa polypeptide was a larva-specific antigen and the mRNA was detectable in microfilariae but not in adult worms and eggs. The λ cD34 gene was not sex linked and was contained in the genome of D. immitis at each stage. The stage-specific expression of the developmentally regulated gene in D. immitis may be controlled primarily at the mRNA level.

scholarly journals Epigenetic regulation of neural cell differentiation plasticity in the adult mammalian brain

2008 ◽  
Vol 105 (46) ◽  
pp. 18012-18017 ◽  
Author(s):  
Jun Kohyama ◽  
Takuro Kojima ◽  
Eriko Takatsuka ◽  
Toru Yamashita ◽  
Jun Namiki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Target Genes ◽  
Epigenetic Modification ◽  
Mammalian Brain ◽  
Cytokine Signaling ◽  
Specific Gene ◽  
Neural Cells ◽  
Specific Gene Expression

Neural stem/progenitor cells (NSCs/NPCs) give rise to neurons, astrocytes, and oligodendrocytes. It has become apparent that intracellular epigenetic modification including DNA methylation, in concert with extracellular cues such as cytokine signaling, is deeply involved in fate specification of NSCs/NPCs by defining cell-type specific gene expression. However, it is still unclear how differentiated neural cells retain their specific attributes by repressing cellular properties characteristic of other lineages. In previous work we have shown that methyl-CpG binding protein transcriptional repressors (MBDs), which are expressed predominantly in neurons in the central nervous system, inhibit astrocyte-specific gene expression by binding to highly methylated regions of their target genes. Here we report that oligodendrocytes, which do not express MBDs, can transdifferentiate into astrocytes both in vitro (cytokine stimulation) and in vivo (ischemic injury) through the activation of the JAK/STAT signaling pathway. These findings suggest that differentiation plasticity in neural cells is regulated by cell-intrinsic epigenetic mechanisms in collaboration with ambient cell-extrinsic cues.

scholarly journals Predicting tissue-specific gene expression from whole blood transcriptome

2020 ◽  
Author(s):  
Mahashweta Basu ◽  
Kun Wang ◽  
Eytan Ruppin ◽  
Sridhar Hannenhalli
Keyword(s):  
Gene Expression ◽  
Whole Blood ◽  
Specific Gene ◽  
Specific Expression ◽  
Tissue Specific ◽  
Complex Disorders ◽  
Tissue Specific Gene ◽  
Tissue Specific Expression ◽  
Specific Gene Expression ◽  
Blood Transcriptome

AbstractComplex diseases are systemic, largely mediated via transcriptional dysregulation in multiple tissues. Thus, knowledge of tissue-specific transcriptome in an individual can provide important information about an individual’s health. Unfortunately, with a few exceptions such as blood, skin, and muscle, an individual’s tissue-specific transcriptome is not accessible through non-invasive means. However, due to shared genetics and regulatory programs between tissues, the transcriptome in blood may be predictive of those in other tissues, at least to some extent. Here, based on GTEx data, we address this question in a rigorous, systematic manner, for the first time. We find that an individual’s whole blood gene expression and splicing profile can predict tissue-specific expression levels in a significant manner (beyond demographic variables) for many genes. On average, across 32 tissues, the expression of about 60% of the genes is predictable from blood expression in a significant manner, with a maximum of 81% of the genes for the musculoskeletal tissue. Remarkably, the tissue-specific expression inferred from the blood transcriptome is almost as good as the actual measured tissue expression in predicting disease state for six different complex disorders, including Hypertension and Type 2 diabetes, substantially surpassing predictors built directly from the blood transcriptome. The code for our pipeline for tissue-specific gene expression prediction – TEEBoT, is provided, enabling others to study its potential translational value in other indications.

Melanocyte-specific gene expression: role of repression and identification of a melanocyte-specific factor, MSF

1994 ◽  
Vol 14 (5) ◽  
pp. 3494-3503
Author(s):  
U Yavuzer ◽  
C R Goding
Keyword(s):  
Gene Expression ◽  
Mutational Analysis ◽  
Site Directed Mutagenesis ◽  
Specific Factor ◽  
Specific Gene ◽  
Binding Motif ◽  
Specific Expression ◽  
Tissue Specific ◽  
Specific Gene Expression

For a gene to be transcribed in a tissue-specific fashion, expression must be achieved in the appropriate cell type and also be prevented in other tissues. As an approach to understanding the regulation of tissue-specific gene expression, we have analyzed the requirements for melanocyte-specific expression of the tyrosinase-related protein 1 (TRP-1) promoter. Positive regulation of TRP-1 expression is mediated by both an octamer-binding motif and an 11-bp element, termed the M box, which is conserved between the TRP-1 and other melanocyte-specific promoters. We show here that, consistent with its ability to activate transcription in a non-tissue-specific fashion, the M box binds the basic-helix-loop-helix factor USF in vitro. With the use of a combination of site-directed mutagenesis and chimeric promoter constructs, additional elements involved in regulating TRP-1 expression were identified. These include the TATA region, which appears to contribute to the melanocyte specificity of the TRP-1 promoter. Mutational analysis also identified two repressor elements, one at the start site, the other located at -240, which function both in melanoma and nonmelanoma cells. In addition, a melanocyte-specific factor, MSF, binds to sites which overlap both repressor elements, with substitution mutations demonstrating that binding by MSF is not required for repression. Although a functional role for MSF has not been unequivocally determined, the location of its binding sites leads us to speculate that it may act as a melanocyte-specific antirepressor during transcription of the endogenous TRP-1 gene.

Influence of epigenetic changes during oocyte growth on nuclear reprogramming after nuclear transfer

1998 ◽  
Vol 10 (8) ◽  
pp. 593 ◽  
Author(s):  
Tomohiro Kono
Keyword(s):  
Gene Expression ◽  
Genomic Imprinting ◽  
Epigenetic Mechanism ◽  
Specific Gene ◽  
Paternal Genome ◽  
Specific Expression ◽  
Oocyte Growth ◽  
Specific Gene Expression ◽  
Mammalian Embryos ◽  
Allele Specific

Genomic imprinting is the epigenetic mechanism that distinguishes whether the loci that are inherited from the maternal or paternal genome lead to parent-specific gene expression. The mechanism also regulates development in mammalian embryos. Genomic imprinting is established after implantation according to the specific markers that are imposed on the genome during gametogenesis; the allele-specific gene expression is then maintained throughout embryogenesis. The genomic imprinting markers are erased and renewed on an own-sex basis only in cells that differentiate into germline cells. This report shows that the epigenetic modifications that occur during oogenesis perform the crucial function of establishing the allele-specific expression of imprinted genes, and also suggests that the epigenetic DNA modification is related to the reprogramming and aberrant development seen in manipulated embryos.

scholarly journals Interaction of Ets-1 and the POU-homeodomain protein GHF-1/Pit-1 reconstitutes pituitary-specific gene expression.

1997 ◽  
Vol 17 (3) ◽  
pp. 1065-1074 ◽  
Author(s):  
A P Bradford ◽  
C Wasylyk ◽  
B Wasylyk ◽  
A Gutierrez-Hartmann
Keyword(s):  
Gene Expression ◽  
Specific Protein ◽  
Protein Domain ◽  
Specific Gene ◽  
Homeodomain Protein ◽  
Specific Expression ◽  
Specific Gene Expression ◽  
Cis Element ◽  
Alternatively Spliced ◽  
Combinatorial Interactions

The pituitary-specific, POU-homeodomain factor GHF-1/Pit-1 is necessary, but not sufficient, for cell-specific expression of prolactin (PRL), growth hormone (GH), and thyrotropin. Combinatorial interactions of GHF-1 with other factors are likely to be required; however, such factors and their mechanisms of action remain to be elucidated. Here we identify Ets-1 as a factor that functionally and physically interacts with GHF-1 to fully reconstitute proximal PRL promoter activity. In contrast, Ets-2 has no effect, and the alternatively spliced GHF-2/Pit-1beta variant fails to synergize with Ets-1. The Ets-1-GHF-1 synergy requires a composite Ets-1-GHF-1 cis element and is dependent on an Ets-1-specific protein domain. Furthermore, the ancestrally related and GHF-1-dependent GH promoter, which lacks this composite element, does not exhibit this response. Finally, Ets-1, but not Ets-2, binds directly to GHF-1 and GHF-2. These data show that a functional interaction of GHF-1 and Ets-1, acting via a composite DNA element, is required to establish lactotroph-specific PRL gene expression, thus providing a molecular mechanism by which GHF-1 can discriminate between the GH and PRL genes. These results underscore the importance of transcription factors that are distinct from, but interact with, homeobox proteins to establish lineage-specific gene expression.

Factors That Determine Cell-Specific Gene Expression in Pancreatic Endocrine Tumor Cells

1989 ◽  
Vol 32 (1-3) ◽  
pp. 61-66 ◽  
Author(s):  
Joel F. Habener ◽  
Mario Vallejo ◽  
James P. Hoeffler
Keyword(s):  
Gene Expression ◽  
Tumor Cells ◽  
Endocrine Tumor ◽  
Pancreatic Endocrine Tumor ◽  
Specific Gene ◽  
Specific Gene Expression

scholarly journals Differential Roles of Hypoxia-Inducible Factor 1α (HIF-1α) and HIF-2α in Hypoxic Gene Regulation

2003 ◽  
Vol 23 (24) ◽  
pp. 9361-9374 ◽  
Author(s):  
Cheng-Jun Hu ◽  
Li-Yi Wang ◽  
Lewis A. Chodosh ◽  
Brian Keith ◽  
M. Celeste Simon
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Target Genes ◽  
Hypoxia Inducible Factor ◽  
Embryonic Stem ◽  
Mouse Embryonic Fibroblast ◽  
Hek293 Cells ◽  
Specific Gene ◽  
Transcriptional Responses ◽  
Inducible Genes

ABSTRACT Transcriptional responses to hypoxia are primarily mediated by hypoxia-inducible factor (HIF), a heterodimer of HIF-α and the aryl hydrocarbon receptor nuclear translocator subunits. The HIF-1α and HIF-2α subunits are structurally similar in their DNA binding and dimerization domains but differ in their transactivation domains, implying they may have unique target genes. Previous studies using Hif-1α−/− embryonic stem and mouse embryonic fibroblast cells show that loss of HIF-1α eliminates all oxygen-regulated transcriptional responses analyzed, suggesting that HIF-2α is dispensable for hypoxic gene regulation. In contrast, HIF-2α has been shown to regulate some hypoxia-inducible genes in transient transfection assays and during embryonic development in the lung and other tissues. To address this discrepancy, and to identify specific HIF-2α target genes, we used DNA microarray analysis to evaluate hypoxic gene induction in cells expressing HIF-2α but not HIF-1α. In addition, we engineered HEK293 cells to express stabilized forms of HIF-1α or HIF-2α via a tetracycline-regulated promoter. In this first comparative study of HIF-1α and HIF-2α target genes, we demonstrate that HIF-2α does regulate a variety of broadly expressed hypoxia-inducible genes, suggesting that its function is not restricted, as initially thought, to endothelial cell-specific gene expression. Importantly, HIF-1α (and not HIF-2α) stimulates glycolytic gene expression in both types of cells, clearly showing for the first time that HIF-1α and HIF-2α have unique targets.

scholarly journals Predicting tissue-specific gene expression from whole blood transcriptome

2021 ◽  
Vol 7 (14) ◽  
pp. eabd6991
Author(s):  
Mahashweta Basu ◽  
Kun Wang ◽  
Eytan Ruppin ◽  
Sridhar Hannenhalli
Keyword(s):  
Gene Expression ◽  
Whole Blood ◽  
Specific Gene ◽  
Specific Expression ◽  
Tissue Specific ◽  
Complex Disorders ◽  
Tissue Specific Gene ◽  
Tissue Specific Expression ◽  
Specific Gene Expression ◽  
Blood Transcriptome

Complex diseases are mediated via transcriptional dysregulation in multiple tissues. Thus, knowing an individual’s tissue-specific gene expression can provide critical information about her health. Unfortunately, for most tissues, the transcriptome cannot be obtained without invasive procedures. Could we, however, infer an individual’s tissue-specific expression from her whole blood transcriptome? Here, we rigorously address this question. We find that an individual’s whole blood transcriptome can significantly predict tissue-specific expression levels for ~60% of the genes on average across 32 tissues, with up to 81% of the genes in skeletal muscle. The tissue-specific expression inferred from the blood transcriptome is almost as good as the actual measured tissue expression in predicting disease state for six different complex disorders, including hypertension and type 2 diabetes, substantially surpassing the blood transcriptome. The code for tissue-specific gene expression prediction, TEEBoT, is provided, enabling others to study its potential translational value in other indications.

scholarly journals Rat Gnrhr promoter directs species-specific gene expression in the pituitary and testes of transgenic mice

2013 ◽  
Vol 50 (3) ◽  
pp. 411-426 ◽  
Author(s):  
Muhammad Ishaq ◽  
Anne-Laure Schang ◽  
Solange Magre ◽  
Jean-Noël Laverrière ◽  
Aurélien Guillou ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Leydig Cells ◽  
Promoter Sequence ◽  
Pcr Analysis ◽  
Marker Genes ◽  
Specific Gene ◽  
Placental Alkaline Phosphatase ◽  
Specific Expression ◽  
Specific Gene Expression

The GnRH receptor (GnRHR) is expressed in several non-pituitary tissues, notably in gonads. However, mechanisms underlying the gonad-specific expression of Gnrhr are not well understood. Here, Gnrhr expression was analysed in the developing testes and pituitaries of rats and transgenic mice bearing the human placental alkaline phosphatase reporter gene (ALPP) under the control of the rat Gnrhr promoter. We showed that the 3.3 kb, but not the pituitary-specific 1.1 kb promoter, directs ALPP expression exclusively to testis Leydig cells from embryonic day 12 onwards. Real-time PCR analysis revealed that promoter activity displayed the same biphasic profile as marker genes in Leydig cells, i.e. abrupt declines after birth followed by progressive rises after a latency phase, in coherence with the differentiation and evolution of foetal and adult Leydig cell lineages. Interestingly, the developmental profile of transgene expression showed high similarity with the endogenous Gnrhr profile in the rat testis, while mouse Gnrhr was only poorly expressed in the mouse testis. In the pituitary, both transgene and Gnrhr were co-expressed at measurable levels with similar ontogenetic profiles, which were markedly distinct from those in the testis. Castration that induced pituitary Gnrhr up-regulation in rats did not affect the mouse Gnrhr. However, it duly up-regulated the transgene. In addition, in LβT2 cells, the rat, but not mouse, Gnrhr promoter was sensitive to GnRH agonist stimulation. Collectively, our data highlight inter-species variations in the expression and regulation of Gnrhr in two different organs and reveal that the rat promoter sequence contains relevant genetic information that dictates rat-specific gene expression in the mouse context.

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