Topically delivered 22 nt siRNAs enhance RNAi silencing of endogenous genes in two species

Planta ◽  
2021 ◽  
Vol 254 (3) ◽  
Author(s):  
Bill Hendrix ◽  
Wei Zheng ◽  
Matthew J. Bauer ◽  
Ericka R. Havecker ◽  
Jennifer T. Mai ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Response To Treatment ◽  
Amaranthus Cruentus ◽  
Rnai Silencing ◽  
Endogenous Genes ◽  
Low Levels ◽  
Green Fluorescent ◽  
Rnai Response ◽  
Very High

Abstract Main conclusion 22 nt siRNAs applied to leaves induce production of transitive sRNAs for targeted genes and can enhance local silencing. Systemic silencing was only observed for a GFP transgene. Abstract RNA interference (RNAi) is a gene silencing mechanism important in regulating gene expression during plant development, response to the environment and defense. Better understanding of the molecular mechanisms of this pathway may lead to future strategies to improve crop traits of value. An abrasion method to deliver siRNAs into leaf cells of intact plants was used to investigate the activities of 21 and 22 nt siRNAs in silencing genes in Nicotiana benthamiana and Amaranthus cruentus. We confirmed that both 21 and 22 nt siRNAs were able to silence a green fluorescent protein (GFP) transgene in treated leaves of N. benthamiana, but systemic silencing of GFP occurred only when the guide strand contained 22 nt. Silencing in the treated leaves of N. benthamiana was demonstrated for three endogenous genes: magnesium cheletase subunit I (CHL-I), magnesium cheletase subunit H (CHL-H), and GENOMES UNCOUPLED4 (GUN4). However, systemic silencing of these endogenous genes was not observed. Very high levels of transitive siRNAs were produced for GFP in response to treatment with 22 nt siRNAs but only low levels were produced in response to a 21 nt siRNA. The endogenous genes tested also produced transitive siRNAs in response to 22 nt siRNAs. 22 nt siRNAs produced greater local silencing phenotypes than 21 nt siRNAs for three of the genes. These special properties of 22 nt siRNAs were also observed for the CHL-H gene in A. cruentus. These experiments suggest a functional role for transitive siRNAs in amplifying the RNAi response.

scholarly journals Topically delivered 22 nt siRNAs enhance RNAi silencing of endogenous genes in two species

2020 ◽  
Author(s):  
Bill Hendrix ◽  
Wei Zheng ◽  
Matthew J. Bauer ◽  
Ericka R. Havecker ◽  
Jennifer T. Mai ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Response To Treatment ◽  
Amaranthus Cruentus ◽  
Rnai Silencing ◽  
Secondary Sirnas ◽  
Endogenous Genes ◽  
Low Levels ◽  
Green Fluorescent ◽  
Rnai Response ◽  
Very High

Abstract22 nt miRNAs or siRNAs have been shown to specifically induce production of transitive (secondary) siRNAs for targeted mRNAs. An abrasion method to deliver dsRNAs into leaf cells of intact plants was used to investigate the activities of 21 and 22 nt siRNAs in silencing genes in Nicotiana benthamiana and Amaranthus cruentus. We confirmed that both 21 and 22 nt siRNAs were able to silence a green fluorescent protein (GFP) transgene in treated leaves of N. benthamiana, but systemic silencing of GFP occurred only when the guide strand contained 22 nt. Silencing in the treated leaves of N. benthamiana was demonstrated for 3 endogenous genes: magnesium cheletase subunit I (CHL-I), magnesium cheletase subunit H (CHL-H), and GUN4. However, systemic silencing of these endogenous genes was not observed. Very high levels of transitive siRNAs were produced for GFP in response to treatment with 22 nt siRNAs, but only low levels were produced in response to a 21 nt siRNA. The endogenous genes tested also had more transitive siRNAs produced in response to 22 nt siRNAs, but the response varied from weak (CHL-I) to strong (CHL-H). 22 nt siRNAs produced greater local silencing phenotypes than 21 nt siRNAs for GFP, CHL-H and GUN4 in N. benthamiana. The special activity of 22 nt siRNAs in producing a greater local phenotype and induction of elevated levels of transitive siRNAs was also shown in A. cruentus for the CHL-H gene. These experiments suggest a functional role for transitive siRNAs in amplifying the RNAi response.

WZsGreen/+: a new green fluorescent protein knock-in mouse model for the study of KIT-expressing cells in gut and cerebellum

2005 ◽  
Vol 22 (3) ◽  
pp. 412-421 ◽  
Author(s):  
Mira Wouters ◽  
Karine Smans ◽  
Jean-Marie Vanderwinden
Keyword(s):  
Small Intestine ◽  
Green Fluorescent Protein ◽  
Gastrointestinal Tract ◽  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Molecular Layer ◽  
Transgenic Animals ◽  
The Novel ◽  
Suitable Alternative ◽  
Green Fluorescent

In the small intestine, interstitial cells of Cajal (ICC) surrounding the myenteric plexus generate the pacemaking slow waves that are essential for an efficient intestinal transit. The underlying molecular mechanisms of the slow wave are poorly known. KIT is currently the sole practical marker for ICC. Attempts to purify living ICC have so far largely failed, due to the loss of the KIT epitope during enzymatic dissociation. Aiming to identify and isolate living ICC, we designed a knock-in strategy to express a fluorescent tag in KIT-expressing cells by inserting the sequence of the novel green fluorescent protein ZsGreen into the first exon of the c-Kit gene, creating a null allele called WZsGreen. In the gastrointestinal tract of heterozygous WZsGreen/+ mice, tiny ZsGreen fluorescent dots were observed in all KIT-expressing ICC populations, with exception of ICC at the deep muscular plexus in small intestine. During development of the gastrointestinal tract, ZsGreen expression followed KIT expression in a spatiotemporal way. Stellate and basket KIT-expressing cells in the molecular layer of the cerebellum also exhibited ZsGreen dots, whereas no ZsGreen was detected in skin, testis, and bone marrow. ZsGreen dot-containing intestinal cells could be isolated from jejunum and maintained alive in culture for at least 3 days. ZsGreen is a suitable alternative to EGFP in transgenic animals. The novel WZsGreen/+ model reported here appears to be a promising tool for live studies of KIT-expressing cells in the gastrointestinal tract and cerebellum and for the further analysis of pacemaker mechanisms.

Induced Expression of the Heat Shock Protein Genes uspA and grpE during Starvation at Low Temperatures and Their Influence on Thermal Resistance of Escherichia coli O157:H7

2003 ◽  
Vol 66 (11) ◽  
pp. 2045-2050 ◽  
Author(s):  
YI ZHANG ◽  
MANSEL W. GRIFFITHS
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Stress Responses ◽  
Thermal Tolerance ◽  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Bacterial Cells ◽  
Induced Expression ◽  
Green Fluorescent ◽  
Shock Proteins

Heat shock proteins play an important role in protecting bacterial cells against several stresses, including starvation. In this study, the promoters for two genes encoding heat shock proteins involved in many stress responses, UspA and GrpE, were fused with the green fluorescent protein (gfp) gene. Thus, the expression of the two genes could be quantified by measuring the fluorescence emitted by the cells under different environmental conditions. The heat resistance levels of starved and nonstarved cells during storage at 5, 10, and 37°C were compared with the levels of expression of the uspA and grpE genes. D52-values (times required for decimal reductions in count at 52°C) increased by 11.5, 14.6, and 18.5 min when cells were starved for 3 h at 37°C, for 24 h at 10°C, and for 2 days at 5°C, respectively. In all cases, these increases were significant (P < 0.01), indicating that the stress imposed by starvation altered the ability of E. coli O157:H7 to survive subsequent heat treatments. Thermal tolerance was correlative with the induction of UspA and GrpE. At 5°C, the change in the thermal tolerance of the pathogen was positively linked to the induced expression of the grpE gene but negatively related to the expression of the uspA gene. The results obtained in this study indicate that UspA plays an important role in starvation-induced thermal tolerance at 37°C but that GrpE may be more involved in regulating this response at lower temperatures. An improvement in our understanding of the molecular mechanisms involved in these cross-protection responses may make it possible to devise strategies to limit their effects.

The Cdk and PCNA domains on p21Cip1 both function to inhibit G1/S progression during hyperoxia

2004 ◽  
Vol 286 (3) ◽  
pp. L506-L513 ◽  
Author(s):  
Christopher E. Helt ◽  
Rhonda J. Staversky ◽  
Yi-Jang Lee ◽  
Robert A. Bambara ◽  
Peter C. Keng ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Fluorescent Protein ◽  
Nuclear Antigen ◽  
Cell Cycle Regulators ◽  
Amino Terminal ◽  
Binding Domains ◽  
Green Fluorescent

This study investigates molecular mechanisms underlying cell cycle arrest when cells are exposed to high levels of oxygen (hyperoxia). Hyperoxia has previously been shown to increase expression of the cell cycle regulators p53 and p21. In the current study, we found that p53-deficient human lung adenocarcinoma H1299 cells failed to induce p21 or growth arrest in G1 when exposed to 95% oxygen. Instead, cells arrested in S and G2. Stable expression of p53 restored induction of p21 and G1 arrest without affecting mRNA expression of the other Cip or INK4 G1 kinase inhibitors. To confirm the role of p21 in G1 arrest, we created H1299 cells with tetracycline-inducible expression of enhanced green fluorescent protein (EGFP), EGFP fused to p21 (EGFp21), or EGFP fused to p27 (EGFp27), a related cell cycle inhibitor. The amino terminus of p21 and p27 bind cyclin-dependent kinases (Cdk), whereas the carboxy terminus of p21 binds the sliding clamp proliferating cell nuclear antigen (PCNA). EGFp21 or EGFp27, but not EGFP by itself, restored G1 arrest during hyperoxia. When separately overexpressed, the amino-terminal Cdk and carboxy-terminal PCNA binding domains of p21 each prevented cells from exiting G1 during exposure. These findings demonstrate that exposure in vitro to hyperoxia exerts G1 arrest through p53-dependent induction of p21 that suppresses Cdk and PCNA activity. Because PCNA also participates in DNA repair, these results raise the possibility that p21 also affects repair of oxidized DNA.

PU.1 determines the self-renewal capacity of erythroid progenitor cells

Blood ◽  
2004 ◽  
Vol 103 (10) ◽  
pp. 3615-3623 ◽  
Author(s):  
Jonathan Back ◽  
Andrée Dierich ◽  
Corinne Bronn ◽  
Philippe Kastner ◽  
Susan Chan
Keyword(s):  
Progenitor Cells ◽  
Fluorescent Protein ◽  
Erythroid Progenitors ◽  
Erythroid Progenitor ◽  
Self Renewal ◽  
Adult Mice ◽  
Erythroid Progenitor Cells ◽  
Low Levels ◽  
Green Fluorescent ◽  
Fluorescent Protein Reporter

Abstract PU.1 is a hematopoietic-specific transcriptional activator that is absolutely required for the differentiation of B lymphocytes and myeloid-lineage cells. Although PU.1 is also expressed by early erythroid progenitor cells, its role in erythropoiesis, if any, is unknown. To investigate the relevance of PU.1 in erythropoiesis, we produced a line of PU.1-deficient mice carrying a green fluorescent protein reporter at this locus. We report here that PU.1 is tightly regulated during differentiation—it is expressed at low levels in erythroid progenitor cells and down-regulated upon terminal differentiation. Strikingly, PU.1-deficient fetal erythroid progenitors lose their self-renewal capacity and undergo proliferation arrest, premature differentiation, and apoptosis. In adult mice lacking one PU.1 allele, similar defects are detected following stress-induced erythropoiesis. These studies identify PU.1 as a novel and critical regulator of erythropoiesis and highlight the versatility of this transcription factor in promoting or preventing differentiation depending on the hematopoietic lineage.

scholarly journals An Unusual ERAD-Like Complex Is Targeted to the Apicoplast of Plasmodium falciparum

2009 ◽  
Vol 8 (8) ◽  
pp. 1134-1145 ◽  
Author(s):  
Simone Spork ◽  
Jan A. Hiss ◽  
Katharina Mandel ◽  
Maik Sommer ◽  
Taco W. A. Kooij ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Molecular Mechanisms ◽  
Protein Transport ◽  
Fluorescent Protein ◽  
Imaging Techniques ◽  
Encoded Proteins ◽  
Red Algal ◽  
Endosymbiotic Event ◽  
Targeting Signal ◽  
Green Fluorescent

ABSTRACT Many apicomplexan parasites, including Plasmodium falciparum, harbor a so-called apicoplast, a complex plastid of red algal origin which was gained by a secondary endosymbiotic event. The exact molecular mechanisms directing the transport of nuclear-encoded proteins to the apicoplast of P. falciparum are not well understood. Recently, in silico analyses revealed a second copy of proteins homologous to components of the endoplasmic reticulum (ER)-associated protein degradation (ERAD) system in organisms with secondary plastids, including the malaria parasite P. falciparum. These proteins are predicted to be endowed with an apicoplast targeting signal and are suggested to play a role in the transport of nuclear-encoded proteins to the apicoplast. Here, we have studied components of this ERAD-derived putative preprotein translocon complex in malaria parasites. Using transfection technology coupled with fluorescence imaging techniques we can demonstrate that the N terminus of several ERAD-derived components targets green fluorescent protein to the apicoplast. Furthermore, we confirm that full-length PfsDer1-1 and PfsUba1 (homologues of yeast ERAD components) localize to the apicoplast, where PfsDer1-1 tightly associates with membranes. Conversely, PfhDer1-1 (a host-specific copy of the Der1-1 protein) localizes to the ER. Our data suggest that ERAD components have been “rewired” to provide a conduit for protein transport to the apicoplast. Our results are discussed in relation to the nature of the apicoplast protein transport machinery.

scholarly journals Molecular Mechanism of the Inhibition of Estradiol-Induced Endometrial Epithelial Cell Proliferation by Clomiphene Citrate

Endocrinology ◽  
2010 ◽  
Vol 151 (1) ◽  
pp. 394-405 ◽  
Author(s):  
Mitsuyoshi Amita ◽  
Toshifumi Takahashi ◽  
Seiji Tsutsumi ◽  
Tsuyoshi Ohta ◽  
Keiko Takata ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Clomiphene Citrate ◽  
Immunofluorescence Assay ◽  
Epithelial Cell Proliferation ◽  
Endometrial Epithelial Cell ◽  
Green Fluorescent

Abstract We examined the molecular mechanisms of the antiestrogenic effects of clomiphene citrate (CC) in the endometrium using two types of cell lines, Ishikawa and EM-E6/E7/hTERT cells. CC or ICI182780 inhibited 17β-estradiol (E2)-induced endometrial cell proliferation and transcriptional activation of the estrogen response element (ERE) gene. We directly visualized the ligand-estrogen receptor (ER)α interaction using green fluorescent protein (GFP)-tagged ERα in a single living cell. Whereas E2 changed the nuclear localization of GFP-ERα to a punctate distribution within 5 min, CC or ICI182780 changed the slower and less mobilization of GFP-ERα compared with E2. Pretreatment with CC or ICI182780 partly prevented the E2-induced nuclear redistribution of GFP-ERα. Fluorescence recovery after photobleaching revealed that GFP-ERα mobility treated with E2 was more rapid than that treated by CC or ICI182780. As coactivator recruitment to the ER is essential for ER-dependent transcription, we examined the interaction between ERα and steroid receptor coactivator-1 (SRC-1). The complex formation between ERα and SRC-1 was significantly increased by E2 but was prevented in the presence of CC or ICI182780 by coimmunoprecipitation. Moreover, the E2-induced colocalization of GFP-ERα and SRC-1 was prevented in the presence of CC or ICI182780 according to an immunofluorescence assay. We also observed that the reduction of SRC-1 using small interfering RNA for SRC-1 resulted in the inhibition of E2-induced cell proliferation and transcriptional activation of the ERE gene. Collectively, these results suggest that CC may inhibit E2-induced endometrial epithelial cell proliferation and ERE transactivation by inhibiting the recruitment of SRC-1 to ERα.

scholarly journals Human induced pluripotent stem cell-derived vocal fold mucosa mimics development and responses to smoke exposure

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Vlasta Lungova ◽  
Xia Chen ◽  
Ziyue Wang ◽  
Christina Kendziorski ◽  
Susan L. Thibeault
Keyword(s):  
Epithelial Cells ◽  
Vocal Fold ◽  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Three Dimensional ◽  
Induced Pluripotent Stem Cell ◽  
Mucosal Inflammation ◽  
Three Dimensional Models ◽  
Green Fluorescent

Abstract Development of treatments for vocal dysphonia has been inhibited by lack of human vocal fold (VF) mucosa models because of difficulty in procuring VF epithelial cells, epithelial cells’ limited proliferative capacity and absence of cell lines. Here we report development of engineered VF mucosae from hiPSC, transfected via TALEN constructs for green fluorescent protein, that mimic development of VF epithelial cells in utero. Modulation of FGF signaling achieves stratified squamous epithelium from definitive and anterior foregut derived cultures. Robust culturing of these cells on collagen-fibroblast constructs produces three-dimensional models comparable to in vivo VF mucosa. Furthermore, we demonstrate mucosal inflammation upon exposure of these constructs to 5% cigarette smoke extract. Upregulation of pro-inflammatory genes in epithelium and fibroblasts leads to aberrant VF mucosa remodeling. Collectively, our results demonstrate that hiPSC-derived VF mucosa is a versatile tool for future investigation of genetic and molecular mechanisms underlying epithelium-fibroblasts interactions in health and disease.

Transcriptional activation by the human Hsp70-associating protein Hap50

2001 ◽  
Vol 114 (10) ◽  
pp. 1839-1845
Author(s):  
Y. Niyaz ◽  
M. Zeiner ◽  
U. Gehring
Keyword(s):  
Transcriptional Activation ◽  
Fluorescent Protein ◽  
Biological Effects ◽  
Cell Types ◽  
Mrna Stabilization ◽  
Activation Of Transcription ◽  
Enhanced Expression ◽  
Endogenous Genes ◽  
Green Fluorescent ◽  
Different Cell Types

We investigated human Hap50, the large isoform of the previously characterized Hsp70/Hsc70-associating protein Hap46, also called BAG-1, for effects on transcriptional activities. Overproduction by transient transfection led to enhanced expression of reporter gene constructs in various cell types using different promoters, suggesting independence of promoter type. Similarly, overexpression of Hap50 resulted in increased levels of poly(A)(+)mRNAs in HeLa, COS-7, 3T3 and HTC cells. Concomitantly, the expression of some selected endogenous genes, such as those coding for c-Jun and the glucocorticoid receptor, was enhanced significantly relative to actin. Nuclear runoff transcription assays using HeLa cells showed that the effect is caused by increased transcription rates rather than mRNA stabilization. Activation of transcription by Hap50 occurred at 37 degrees C and did not require prior thermal stress, as is the case for Hap46. In accordance with these biological effects, Hap50 is localized exclusively in the nuclear compartment of different cell types, whereas Hap46 is mostly cytoplasmic in unstressed cells, as revealed by use of fusion constructs with green fluorescent protein. High cellular levels of Hap50 were found to make cells less susceptible to adverse environmental effects such as heat stress. Our data suggest that Hap50 is a nuclear protein that acts in cells to increase the transcription of various genes.

Modulation of p210BCR-ABL activity in transduced primary human hematopoietic cells controls lineage programming

Blood ◽  
2002 ◽  
Vol 99 (9) ◽  
pp. 3197-3204 ◽  
Author(s):  
Yves Chalandon ◽  
Xiaoyan Jiang ◽  
Glen Hazlewood ◽  
Slade Loutet ◽  
Eibhlin Conneally ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Kinase Inhibitor ◽  
Hematopoietic Cells ◽  
Erythroid Differentiation ◽  
Human Leukemia ◽  
Retroviral Transduction ◽  
Sti 571 ◽  
Human Cd34 ◽  
Green Fluorescent

Abstract Retroviral transduction of primary hematopoietic cells with human oncogenes provides a powerful approach to investigating the molecular mechanisms controlling the normal proliferation and differentiation of these cells. Here we show that primitive human CD34+ cord blood cells, including multipotent as well as granulopoietic- and erythroid-restricted progenitors, can be efficiently transduced with a MSCV-BCR-ABL-IRES-GFP retrovirus, resulting in the sustained expression by their progeny of very high levels of tyrosine phosphorylated p210BCR-ABL. Interestingly, even in the presence of growth factors that supported the exclusive production of granulopoietic cells from green fluorescent protein (GFP)–transduced control cells, BCR-ABL–transduced progenitor subpopulations generated large numbers of erythropoietin-independent terminally differentiating erythroid cells and reduced numbers of granulopoietic cells. Analyses of individual clones generated by single transduced cells in both semisolid and liquid cultures showed this BCR-ABL–induced erythroid differentiation response to be elicited at a high frequency from all types of transduced CD34+ cells independent of their apparent prior lineage commitment status. Additional experiments showed that this erythroid differentiation response was largely prevented when the cells were transduced and maintained in the presence of the BCR-ABL–specific tyrosine kinase inhibitor, STI-571. These findings indicate that overexpression of BCR-ABL in primary human hematopoietic cells can activate an erythroid differentiation program in apparently granulopoietic-restricted cells through a BCR-ABL kinase-dependent mechanism, thus providing a new molecular tool for elucidating mechanisms underlying lineage fate determination in human hematopoietic cells and infidelity in human leukemia.

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