Reassessment of murine APOBEC1 as a retrovirus restriction factor in vivo

ABSTRACT Understanding the interactions between rabies virus (RABV) and individual host cell proteins is critical for the development of targeted therapies. Here we report that interferon-induced protein with tetratricopeptide repeats 2 (Ifit2), an interferon-stimulated gene (ISG) with possible RNA-binding capacity, is an important restriction factor for rabies virus. When Ifit2 was depleted, RABV grew more quickly in mouse neuroblastoma cells in vitro. This effect was replicated in vivo, where Ifit2 knockout mice displayed a dramatically more severe disease phenotype than wild-type mice after intranasal inoculation of RABV. This increase in pathogenicity correlated to an increase in RABV mRNA and live viral load in the brain, as well as to an accelerated spread to brain regions normally affected by this RABV model. These results suggest that Ifit2 exerts its antiviral effect mainly at the level of viral replication, as opposed to functioning as a mechanism that restricts viral entry/egress or transports RABV particles through axons. IMPORTANCE Rabies is a fatal zoonotic disease with a nearly 100% case fatality rate. Although there are effective vaccines for rabies, this disease still takes the lives of about 50,000 people each year. Victims tend to be children living in regions without comprehensive medical infrastructure who present to health care workers too late for postexposure prophylaxis. The protein discussed in our report, Ifit2, is found to be an important restriction factor for rabies virus, acting directly or indirectly against viral replication. A more nuanced understanding of this interaction may reveal a step of a pathway or site at which the system could be exploited for the development of a targeted therapy.

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Comprehensive Antiretroviral Restriction Factor Profiling Reveals the Evolutionary Imprint of the ex Vivo and in Vivo IFN-β Response in HTLV-1-Associated Neuroinflammation

Frontiers in Microbiology ◽

10.3389/fmicb.2018.00985 ◽

2018 ◽

Vol 9 ◽

Cited By ~ 6

Author(s):

Fabio E. Leal ◽

Soraya Maria Menezes ◽

Emanuela A. S. Costa ◽

Phillip M. Brailey ◽

Lucio Gama ◽

...

Keyword(s):

Ex Vivo ◽

Restriction Factor

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Deaminase-Dead Mouse APOBEC3 Is anIn VivoRetroviral Restriction Factor

Journal of Virology ◽

10.1128/jvi.00168-18 ◽

2018 ◽

Vol 92 (11) ◽

Cited By ~ 10

Author(s):

Spyridon Stavrou ◽

Wenming Zhao ◽

Kristin Blouch ◽

Susan R. Ross

Keyword(s):

Transgenic Mice ◽

Cytidine Deaminase ◽

Restriction Factor ◽

Wild Type ◽

Restriction Factors ◽

Dead Mouse ◽

Apobec3 Proteins ◽

Cytidine Deamination ◽

Retrovirus Infection

ABSTRACTThe apolipoprotein B editing complex 3 (APOBEC3) proteins are potent retroviral restriction factors that are under strong positive selection, both in terms of gene copy number and sequence diversity. A common feature of all the members of the APOBEC3 family is the presence of one or two cytidine deamination domains, essential for cytidine deamination of retroviral reverse transcripts as well as packaging into virions. Several studies have indicated that human and mouse APOBEC3 proteins restrict retrovirus infection via cytidine deaminase (CD)-dependent and -independent means. To understand the relative contribution of CD-independent restrictionin vivo, we created strains of transgenic mice on an APOBEC3 knockout background that express a deaminase-dead mouse APOBEC3 due to point mutations in both CD domains (E73Q/E253Q). Here, we show that the CD-dead APOBEC3 can restrict murine retrovirusesin vivo. Moreover, unlike the wild-type protein, the mutant APOBEC3 is not packaged into virions but acts only as a cell-intrinsic restriction factor that blocks reverse transcription by incoming viruses. Finally, we show that wild-type and CD-dead mouse APOBEC3 can bind to murine leukemia virus (MLV) reverse transcriptase. Our findings suggest that the mouse APOBEC3 cytidine deaminase activity is not required for retrovirus restriction.IMPORTANCEAPOBEC3 proteins are important host cellular restriction factors essential for restricting retrovirus infection by causing mutations in the virus genome and by blocking reverse transcription. While both methods of restriction functionin vitro, little is known about their role duringin vivoinfection. By developing transgenic mice with mutations in the cytidine deamination domains needed for enzymatic activity and interaction with viral RNA, we show that APOBEC3 proteins can still restrictin vivoinfection by interacting with reverse transcriptase and blocking its activity. These studies demonstrate that APOBEC3 proteins have evolved multiple means for blocking retrovirus infection and that all of these means functionin vivo.

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Dynamic Regulation of Host Restriction Factor Expression over the Course of HIV-1 Infection In Vivo

Journal of Virology ◽

10.1128/jvi.01771-14 ◽

2014 ◽

Vol 88 (19) ◽

pp. 11624-11629 ◽

Cited By ~ 13

Author(s):

R. A. S. Raposo ◽

M. Abdel-Mohsen ◽

X. Deng ◽

F. M. Hecht ◽

C. D. Pilcher ◽

...

Keyword(s):

Restriction Factor ◽

Dynamic Regulation ◽

Host Restriction ◽

Host Restriction Factor ◽

Factor Expression ◽

Hiv 1

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Dynamic Modulation of Expression of Lentiviral Restriction Factors in Primary CD4+ T Cells following Simian Immunodeficiency Virus Infection

Journal of Virology ◽

10.1128/jvi.02189-16 ◽

2017 ◽

Vol 91 (7) ◽

Cited By ~ 1

Author(s):

Andrew R. Rahmberg ◽

Premeela A. Rajakumar ◽

James M. Billingsley ◽

R. Paul Johnson

Keyword(s):

T Cells ◽

Peripheral Blood ◽

Rhesus Macaques ◽

Restriction Factor ◽

Restriction Factors ◽

Dynamic Modulation ◽

Immunodeficiency Virus ◽

Factor Expression ◽

Siv Infection

ABSTRACT Although multiple restriction factors have been shown to inhibit HIV/SIV replication, little is known about their expression in vivo. Expression of 45 confirmed and putative HIV/SIV restriction factors was analyzed in CD4+ T cells from peripheral blood and the jejunum in rhesus macaques, revealing distinct expression patterns in naive and memory subsets. In both peripheral blood and the jejunum, memory CD4+ T cells expressed higher levels of multiple restriction factors compared to naive cells. However, relative to their expression in peripheral blood CD4+ T cells, jejunal CCR5+ CD4+ T cells exhibited significantly lower expression of multiple restriction factors, including APOBEC3G, MX2, and TRIM25, which may contribute to the exquisite susceptibility of these cells to SIV infection. In vitro stimulation with anti-CD3/CD28 antibodies or type I interferon resulted in upregulation of distinct subsets of multiple restriction factors. After infection of rhesus macaques with SIVmac239, the expression of most confirmed and putative restriction factors substantially increased in all CD4+ T cell memory subsets at the peak of acute infection. Jejunal CCR5+ CD4+ T cells exhibited the highest levels of SIV RNA, corresponding to the lower restriction factor expression in this subset relative to peripheral blood prior to infection. These results illustrate the dynamic modulation of confirmed and putative restriction factor expression by memory differentiation, stimulation, tissue microenvironment and SIV infection and suggest that differential expression of restriction factors may play a key role in modulating the susceptibility of different populations of CD4+ T cells to lentiviral infection. IMPORTANCE Restriction factors are genes that have evolved to provide intrinsic defense against viruses. HIV and simian immunodeficiency virus (SIV) target CD4+ T cells. The baseline level of expression in vivo and degree to which expression of restriction factors is modulated by conditions such as CD4+ T cell differentiation, stimulation, tissue location, or SIV infection are currently poorly understood. We measured the expression of 45 confirmed and putative restriction factors in primary CD4+ T cells from rhesus macaques under various conditions, finding dynamic changes in each state. Most dramatically, in acute SIV infection, the expression of almost all target genes analyzed increased. These are the first measurements of many of these confirmed and putative restriction factors in primary cells or during the early events after SIV infection and suggest that the level of expression of restriction factors may contribute to the differential susceptibility of CD4+ T cells to SIV infection.

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In vivo expression profile of the antiviral restriction factor and tumor-targeting antigen CD317/BST-2/HM1.24/tetherin in humans

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1101684108 ◽

2011 ◽

Vol 108 (33) ◽

pp. 13688-13693 ◽

Cited By ~ 62

Author(s):

E. Erikson ◽

T. Adam ◽

S. Schmidt ◽

J. Lehmann-Koch ◽

B. Over ◽

...

Keyword(s):

Expression Profile ◽

Tumor Targeting ◽

Restriction Factor ◽

In Vivo Expression

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Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050287 ◽

1974 ◽

Vol 32 ◽

pp. 54-55

Author(s):

S. Phyllis Steamer ◽

Rosemarie L. Devine

Keyword(s):

Structural Changes ◽

Radiation Treatment ◽

Arterial Stenosis ◽

Ultrastructural Changes ◽

Vascular Effects ◽

Microvascular Changes ◽

Surrounding Connective Tissue ◽

Fission Neutrons ◽

Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

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Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053425 ◽

1982 ◽

Vol 40 ◽

pp. 142-145

Author(s):

E. J. Kollar

Keyword(s):

Connective Tissue ◽

Oral Mucosa ◽

Basal Lamina ◽

Functional Derivatives ◽

Specific Source ◽

Dental Epithelium ◽

Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

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Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053711 ◽

1982 ◽

Vol 40 ◽

pp. 210-211

Author(s):

M.J. Murphy ◽

R.R. Price ◽

J.C. Sloman

Keyword(s):

Cultured Cells ◽

Human Tumor ◽

Cell Type ◽

Tumor Mass ◽

Initial Cell ◽

Cloning Assay ◽

Human Tumor Cloning ◽

The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

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