scholarly journals Gene Knockout Shows That PML (TRIM19) Does Not Restrict the Early Stages of HIV-1 Infection in Human Cell Lines

mSphere ◽  
2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Nasser Masroori ◽  
Pearl Cherry ◽  
Natacha Merindol ◽  
Jia-xin Li ◽  
Caroline Dufour ◽  
...  
Keyword(s):  
Cell Lines ◽  
Human Cell ◽  
Gene Knockout ◽  
Human Cells ◽  
Restriction Factor ◽  
Type I ◽  
Human Cell Lines ◽  
Early Stages ◽  
Human T Cell ◽  
Hiv 1

ABSTRACTThe PML (promyelocytic leukemia) protein is a member of the TRIM family, a large group of proteins that show high diversity in functions but possess a common tripartite motif giving the family its name. We and others recently reported that both murine PML (mPML) and human PML (hPML) strongly restrict the early stages of infection by HIV-1 and other lentiviruses when expressed in mouse embryonic fibroblasts (MEFs). This restriction activity was found to contribute to the type I interferon (IFN-I)-mediated inhibition of HIV-1 in MEFs. Additionally, PML caused transcriptional repression of the HIV-1 promoter in MEFs. In contrast, the modulation of the early stages of HIV-1 infection of human cells by PML has been investigated by RNA interference, with unclear results. In order to conclusively determine whether PML restricts HIV-1 or not in human cells, we used the clustered regularly interspaced short palindromic repeat with Cas9 (CRISPR-Cas9) system to knock out its gene in epithelial, lymphoid, and monocytic human cell lines. Infection challenges showed that PML knockout had no effect on the permissiveness of these cells to HIV-1 infection. IFN-I treatments inhibited HIV-1 equally whether PML was expressed or not. Overexpression of individual hPML isoforms, or of mPML, in a human T cell line did not restrict HIV-1. The presence of PML was not required for the restriction of nonhuman retroviruses by TRIM5α (another human TRIM protein), and TRIM5α was inhibited by arsenic trioxide through a PML-independent mechanism. We conclude that PML is not a restriction factor for HIV-1 in human cell lines representing diverse lineages.IMPORTANCEPML is involved in innate immune mechanisms against both DNA and RNA viruses. Although the mechanism by which PML inhibits highly divergent viruses is unclear, it was recently found that it can increase the transcription of interferon-stimulated genes (ISGs). However, whether human PML inhibits HIV-1 has been debated. Here we provide unambiguous, knockout-based evidence that PML does not restrict the early postentry stages of HIV-1 infection in a variety of human cell types and does not participate in the inhibition of HIV-1 by IFN-I. Although this study does not exclude the possibility of other mechanisms by which PML may interfere with HIV-1, we nonetheless demonstrate that PML does not generally act as an HIV-1 restriction factor in human cells and that its presence is not required for IFN-I to stimulate the expression of anti-HIV-1 genes. These results contribute to uncovering the landscape of HIV-1 inhibition by ISGs in human cells.

scholarly journals Gene knockout shows that PML (TRIM19) does not restrict the early stages of HIV-1 infection in human cell lines

2017 ◽  
Author(s):  
Nasser Masroori ◽  
Pearl Cherry ◽  
Natacha Merindol ◽  
Jia-xin Li ◽  
Caroline Dufour ◽  
...  
Keyword(s):  
Cell Lines ◽  
Human Cell ◽  
Gene Knockout ◽  
Human Cells ◽  
Restriction Factor ◽  
Type I ◽  
Human Cell Lines ◽  
Early Stages ◽  
Human T Cell ◽  
Hiv 1

AbstractThe PML (promyelocytic leukemia) protein is a member of the TRIM family, a large group of proteins that show high diversity in functions but possess a common tripartite motif giving the family its name. We and others recently reported that both murine PML (mPML) and human PML (hPML) strongly restrict the early stages of infection by HIV-1 and other lentiviruses when expressed in mouse embryonic fibroblasts (MEFs). This restriction activity was found to contribute to the type I interferon (IFN-I)-mediated inhibition of HIV-1 in MEFs. Additionally, PML caused transcriptional repression of the HIV-1 promoter in MEFs. By contrast, the modulation of the early stages of HIV-1 infection of human cells by PML has been investigated by RNAi with unclear results. In order to conclusively determine whether PML restricts HIV-1 or not in human cells, we used CRISPR-Cas9 to knock out its gene in epithelial, lymphoid and monocytic human cell lines. Infection challenges showed that PML knockout had no effect on the permissiveness of these cells to HIV-1 infection. IFN-I treatments inhibited HIV-1 equally whether PML was expressed or not. Over-expression of individual hPML isoforms, or of mPML, in a human T cell line did not restrict HIV-1. The presence of PML was not required for the restriction of nonhuman retroviruses by TRIM5α was inhibited by arsenic trioxide through a PML-independent mechanism. We conclude that PML is not a restriction factor for HIV-1 in human cell lines representing diverse lineages.ImportancePML is involved in innate immune mechanisms against both DNA and RNA viruses. Although the mechanism by which PML inhibits highly divergent viruses is unclear, it was recently found that it can increase the transcription of interferon-stimulated genes (ISGs). However, whether human PML inhibits HIV-1 has been debated. Here we provide unambiguous, knockout-based evidence that PML does not restrict the early post-entry stages of HIV-1 infection in a variety of human cell types and does not participate in the inhibition of HIV-1 by IFN-I. Although this study does not exclude the possibility of other mechanisms by which PML may interfere with HIV-1, we nonetheless demonstrate that PML does not generally act as an HIV-1 restriction factor in human cells and that its presence is not required for IFN-I to stimulate the expression of anti-HIV-1 genes. These results contribute to uncovering the landscape of HIV-1 inhibition by ISGs in human cells.

Altered gene expression during cellular aging

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 386-389 ◽  
Author(s):  
James R. Smith ◽  
Olivia M. Pereira-Smith
Keyword(s):  
Gene Expression ◽  
Dna Synthesis ◽  
Cell Lines ◽  
Cellular Senescence ◽  
Human Cell ◽  
Messenger Rna ◽  
Human Cells ◽  
Cellular Aging ◽  
Human Cell Lines ◽  
Normal Human

The limited division potential of normal human diploid fibroblasts in culture represents a model system for cellular aging. Observations indicate cellular senescence is an active process. Senescent cells, although unable to divide, are actively metabolizing. Hybrids from fusion of normal and immortal human cells exhibit limited division potential, suggesting that the phenotype of cellular senescence is dominant and supporting the hypothesis that senescence is genetically programmed. Fusion of immortal human cell lines with each other has identified four complementation groups for indefinite division. This indicates that a limited number of specific genes or processes are involved in senescence. Senescent cells express highly abundant DNA synthesis inhibitory messenger RNAs and produce a surface membrane associated protein inhibitor of DNA synthesis not expressed in young cells. Senescent cell membranes were used as immunogen to generate three monoclonal antibodies reacting specifically with senescent but not young cells in several normal human cell lines. We have also found that fibronectin messenger RNA accumulates to high levels in senescent cells. The role of these changes in gene expression in senescence is being explored.Key words: cellular senescence, human cells.

scholarly journals Editing of the Human TRIM5 Gene to Introduce Mutations with the Potential to Inhibit HIV-1

2017 ◽  
Author(s):  
Caroline Dufour ◽  
Alix Claudel ◽  
Nicolas Joubarne ◽  
Natacha Merindol ◽  
Tara Maisonnet ◽  
...  
Keyword(s):  
Cell Line ◽  
Type I Interferon ◽  
Human Cells ◽  
Restriction Factor ◽  
Type I ◽  
Dna Transfection ◽  
Homology Directed Repair ◽  
Cell Clones ◽  
Overall Efficiency ◽  
Hiv 1

ABSTRACTThe type I interferon (IFN-I)-inducible human restriction factor TRIM5α inhibits the infection of human cells by specific nonhuman retroviruses, such as N-MLV and EIAV, but does not generally target HIV-1. However, the introduction of two aminoacid substitutions, R332G and R355G, in the human TRIM5α (huTRIM5α) domain responsible for retroviral capsid recognition leads to efficient HIV-1 restriction. Using a DNA transfection-based CRISPR-Cas9 genome editing protocol, we successfully mutated TRIM5 to its HIV-1-restrictive version by homology-directed repair (HDR) in HEK293T cells. Nine clones bearing at least one HDR-edited TRIM5 allele containing both mutations were isolated (5.6% overall efficiency), whereas another one contained only the R332G mutation. Of concern, several of these HDR-edited clones contained on-target undesired mutations, and none had all the alleles corrected. We observed a lack of HIV-1 restriction in the cell clones generated, even when cells were stimulated with IFN-I prior to infection. This, however, was partly explained by the unexpectedly low potential for TRIM5α-mediated restriction activity in this cell line. Our study demonstrates the feasibility of editing the TRIM5 gene to in human cells and identifies the main challenges to be addressed in order to use this approach to confer protection from HIV-1.

scholarly journals Relative cytotoxicity of complexes of platinum(II) and palladium(II) against pure cell culture Paramecium caudatum and human cell lines A431 and HaCaT

2018 ◽  
Vol 7 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Aleksei Vladimirovich Eremin ◽  
Roman Vladimirovich Suezov ◽  
Polina Sergeevna Grishina ◽  
Alexander Ivanovich Ponyaev ◽  
Nicolay Leonidovich Medvedskiy
Keyword(s):  
Cell Culture ◽  
Cell Lines ◽  
Mtt Assay ◽  
Human Cell ◽  
Human Cells ◽  
Epidermoid Carcinoma ◽  
Binuclear Complexes ◽  
Human Cell Lines ◽  
Paramecium Caudatum ◽  
Pure Cell

The results of cytotoxicity cis-diamine mono- and binuclear complexes of platinum(II) and palladium(II) are presented. The cytotoxicity was investigated by the method of biotesting with Paramecium caudatum and by MTT-assay with human cells: epidermoid carcinoma A431 and minimal transformed aneuploid keratinocytes HaCaT. Cytotoxicity of complexes towards protists is higher than against human cells, however, comparatively, HaCaT is more sensitive than A431 by the treatment all complexes. It is noted that cytotoxicity of palladium(II) complexes is higher than the analogues with platinum(II).

scholarly journals HBO1 (KAT7) Does Not Have an Essential Role in Cell Proliferation, DNA Replication, or Histone 4 Acetylation in Human Cells

2019 ◽  
Vol 40 (4) ◽  
Author(s):  
Andrew J. Kueh ◽  
Samantha Eccles ◽  
Leonie Tang ◽  
Alexandra L. Garnham ◽  
Rose E. May ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Adhesion ◽  
Dna Replication ◽  
Cell Lines ◽  
Human Cell ◽  
Human Cells ◽  
Human Cell Lines ◽  
Hela Cell Lines ◽  
Mouse Tissues ◽  
Sirna Knockdown

ABSTRACT HBO1 (MYST2/KAT7) is essential for histone 3 lysine 14 acetylation (H3K14ac) but is dispensable for H4 acetylation and DNA replication in mouse tissues. In contrast, previous studies using small interfering RNA (siRNA) knockdown in human cell lines have suggested that HBO1 is essential for DNA replication. To determine if HBO1 has distinctly different roles in immortalized human cell lines and normal mouse cells, we performed siRNA knockdown of HBO1. In addition, we used CRISPR/Cas9 to generate 293T, MCF7, and HeLa cell lines lacking HBO1. Using both techniques, we show that HBO1 is essential for all H3K14ac in human cells and is unlikely to have a direct effect on H4 acetylation and only has minor effects on cell proliferation. Surprisingly, the loss of HBO1 and H3K14ac in HeLa cells led to the secondary loss of almost all H4 acetylation after 4 weeks. Thus, HBO1 is dispensable for DNA replication and cell proliferation in immortalized human cells. However, while cell proliferation proceeded without HBO1 and H3K14ac, HBO1 gene deletion led to profound changes in cell adhesion, particularly in 293T cells. Consistent with this phenotype, the loss of HBO1 in both 293T and HeLa principally affected genes mediating cell adhesion, with comparatively minor effects on other cellular processes.

Productive infection of both CD4+ and CD4− human cell lines with HIV-1, HIV-2 and SIVagm

AIDS ◽  
1990 ◽  
Vol 4 (6) ◽  
pp. 537-544 ◽  
Author(s):  
Albrecht Werner ◽  
Gudrun Winskowsky ◽  
Klaus Cichutek ◽  
Stephen G. Norley ◽  
Reinhard Kurth
Keyword(s):  
Cell Lines ◽  
Human Cell ◽  
Productive Infection ◽  
Human Cell Lines ◽  
Hiv 1

scholarly journals Evaluation and Design of Genome-wide CRISPR/Cas9 Knockout Screens

2017 ◽  
Author(s):  
Traver Hart ◽  
Amy Tong ◽  
Katie Chan ◽  
Jolanda Van Leeuwen ◽  
Ashwin Seetharaman ◽  
...  
Keyword(s):  
Cell Lines ◽  
Human Cell ◽  
Viral Vectors ◽  
Human Cancer ◽  
Gene Knockout ◽  
Essential Genes ◽  
Human Cell Lines ◽  
Protein Coding ◽  
Mammalian Cell Lines ◽  
Genome Scale

AbstractThe adaptation of CRISPR/Cas9 technology to mammalian cell lines is transforming the study of human functional genomics. Pooled libraries of CRISPR guide RNAs (gRNAs), targeting human protein-coding genes and encoded in viral vectors, have been used to systematically create gene knockouts in a variety of human cancer and immortalized cell lines, in an effort to identify whether these knockouts cause cellular fitness defects. Previous work has shown that CRISPR screens are more sensitive and specific than pooled library shRNA screens in similar assays, but currently there exists significant variability across CRISPR library designs and experimental protocols. In this study, we re-analyze 17 genome-scale knockout screens in human cell lines from three research groups using three different genome-scale gRNA libraries, using the Bayesian Analysis of Gene Essentiality (BAGEL) algorithm to identify essential genes, to refine and expand our previously defined set of human core essential genes, from 360 to 684 genes. We use this expanded set of reference Core Essential Genes (CEG2), plus empirical data from six CRISPR knockout screens, to guide the design of a sequence-optimized gRNA library, the Toronto KnockOut version 3.0 (TKOv3) library. We demonstrate the high effectiveness of the library relative to reference sets of essential and nonessential genes as well as other screens using similar approaches. The optimized TKOv3 library, combined with the CEG2 reference set, provide an efficient, highly optimized platform for performing and assessing gene knockout screens in human cell lines.

scholarly journals Hydroxylation of the Acetyltransferase NAA10 Trp38 Is Not an Enzyme-Switch in Human Cells

2021 ◽  
Vol 22 (21) ◽  
pp. 11805
Author(s):  
Rasmus Ree ◽  
Karoline Krogstad ◽  
Nina McTiernan ◽  
Magnus E. Jakobsson ◽  
Thomas Arnesen
Keyword(s):  
Catalytic Activity ◽  
Cell Lines ◽  
Human Cell ◽  
Hypoxia Inducible Factor ◽  
Human Cells ◽  
Human Proteome ◽  
Human Cell Lines ◽  
Structural Studies ◽  
Hypoxia Inducible Factor 1Α ◽  
Lysine Acetyltransferase

NAA10 is a major N-terminal acetyltransferase (NAT) that catalyzes the cotranslational N-terminal (Nt-) acetylation of 40% of the human proteome. Several reports of lysine acetyltransferase (KAT) activity by NAA10 exist, but others have not been able to find any NAA10-derived KAT activity, the latter of which is supported by structural studies. The KAT activity of NAA10 towards hypoxia-inducible factor 1α (HIF-1α) was recently found to depend on the hydroxylation at Trp38 of NAA10 by factor inhibiting HIF-1α (FIH). In contrast, we could not detect hydroxylation of Trp38 of NAA10 in several human cell lines and found no evidence that NAA10 interacts with or is regulated by FIH. Our data suggest that NAA10 Trp38 hydroxylation is not a switch in human cells and that it alters its catalytic activity from a NAT to a KAT.

scholarly journals SARS-CoV-2 disrupts proximal elements in the JAK-STAT pathway

2021 ◽  
Author(s):  
Da-Yuan Chen ◽  
Nazimuddin Khan ◽  
Brianna J. Close ◽  
Raghuveera K. Goel ◽  
Benjamin Blum ◽  
...  
Keyword(s):  
Cell Lines ◽  
Human Cell ◽  
Type I Interferon ◽  
Cell Types ◽  
Janus Kinase ◽  
Type I ◽  
Human Cell Lines ◽  
Interferon Signaling ◽  
Interferon Receptor ◽  
Stat Pathway

SARS-CoV-2 can infect multiple organs, including lung, intestine, kidney, heart, liver, and brain. The molecular details of how the virus navigates through diverse cellular environments and establishes replication are poorly defined. Here, we generated a panel of phenotypically diverse, SARS-CoV-2-infectable human cell lines representing different body organs and performed longitudinal survey of cellular proteins and pathways broadly affected by the virus. This revealed universal inhibition of interferon signaling across cell types following SARS-CoV-2 infection. We performed systematic analyses of the JAK-STAT pathway in a broad range of cellular systems, including immortalized cells and primary-like cardiomyocytes, and found that SARS-CoV-2 targeted the proximal pathway components, including Janus kinase 1 (JAK1), tyrosine kinase 2 (Tyk2), and the interferon receptor subunit 1 (IFNAR1), resulting in cellular desensitization to type I IFN. Detailed mechanistic investigation of IFNAR1 showed that the protein underwent ubiquitination upon SARS-CoV-2 infection. Furthermore, chemical Inhibition of JAK kinases enhanced infection of stem cell-derived cultures, indicating that the virus benefits from inhibiting the JAK-STAT pathway. These findings suggest that the suppression of interferon signaling is a mechanism widely used by the virus to evade antiviral innate immunity, and that targeting the viral mediators of immune evasion may help block virus replication in patients with COVID-19. IMPORTANCE SARS-CoV-2 can infect various organs in the human body, but the molecular interface between the virus and these organs remains unexplored. In this study, we generated a panel of highly infectable human cell lines originating from various body organs and employed these cells to identify cellular processes commonly or distinctly disrupted by SARS-CoV-2 in different cell types. One among the universally impaired processes was interferon signaling. Systematic analysis of this pathway in diverse culture systems showed that SARS-CoV-2 targets the proximal JAK-STAT pathway components, destabilizes the type I interferon receptor though ubiquitination, and consequently renders the infected cells resistant to type I interferon. These findings illuminate how SARS-CoV-2 can continue to propagate in different tissues even in the presence of a disseminated innate immune response.

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