scholarly journals Protein arginine methylation during lytic adenovirus infection

2004 ◽  
Vol 383 (2) ◽  
pp. 259-265 ◽  
Author(s):  
Julia KZHYSHKOWSKA ◽  
Elisabeth KREMMER ◽  
Markus HOFMANN ◽  
Hans WOLF ◽  
Thomas DOBNER
Keyword(s):  
Cell Function ◽  
Arginine Methylation ◽  
Productive Infection ◽  
Mrna Metabolism ◽  
Infected Cells ◽  
Protein Arginine Methylation ◽  
Adenovirus E1b ◽  
Protein Arginine Methyltransferase 1

Arginine methylation of proteins affects major processes in the cell, including transcriptional regulation, mRNA metabolism, signal transduction and protein sorting. Arginine methylation of Ad (adenovirus) E1B 55-kDa-associated protein E1B-AP5 was recently described by us [Kzhyshkowska, Schutt, Liss, Kremmer, Stauber, Wolf and Dobner (2001) Biochem. J. 358, 305–314]. In this first example of protein arginine methylation analysis in Ad-infected cells, we investigated methylation of the E1B-AP5 and the viral L4-100 kDa protein. We demonstrate that E1B-AP5 methylation is enhanced during the course of infection in a cell-type-specific manner. We also show that L4-100 kDa is efficiently methylated in Ad-infected cells. L4-100 kDa formed complex with methyltransferase in vivo during productive infection, and can be methylated by HRMT1L2 (human protein arginine methyltransferase 1) in vitro. Comparative analysis of E1B-AP5 and L4-100 kDa protein methylation in Ad-infected HeLa, MCF-7 and H1299 cells revealed that the profile of protein arginine methylation correlates with the efficiency of Ad proteins production. Our results suggest that protein arginine methylation is an important host-cell function required for efficient Ad replication.

scholarly journals PRMT7 regulates RNA-binding capacity and protein stability in Leishmania parasites

2020 ◽  
Vol 48 (10) ◽  
pp. 5511-5526
Author(s):  
Tiago R Ferreira ◽  
Adam A Dowle ◽  
Ewan Parry ◽  
Eliza V C Alves-Ferreira ◽  
Karen Hogg ◽  
...  
Keyword(s):  
Protein Modification ◽  
Transcriptional Control ◽  
Leishmania Major ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Capacity ◽  
Arginine Methylation ◽  
Mrna Metabolism

Abstract RNA binding proteins (RBPs) are the primary gene regulators in kinetoplastids as transcriptional control is nearly absent, making Leishmania an exceptional model for investigating methylation of non-histone substrates. Arginine methylation is an evolutionarily conserved protein modification catalyzed by Protein aRginine Methyl Transferases (PRMTs). The chromatin modifier PRMT7 is the only Type III PRMT found in higher eukaryotes and a restricted number of unicellular eukaryotes. In Leishmania major, PRMT7 is a cytoplasmic protein implicit in pathogenesis with unknown substrates. Using comparative methyl-SILAC proteomics for the first time in protozoa, we identified 40 putative targets, including 17 RBPs hypomethylated upon PRMT7 knockout. PRMT7 can modify Alba3 and RBP16 trans-regulators (mammalian RPP25 and YBX2 homologs, respectively) as direct substrates in vitro. The absence of PRMT7 levels in vivo selectively reduces Alba3 mRNA-binding capacity to specific target transcripts and can impact the relative stability of RBP16 in the cytoplasm. RNA immunoprecipitation analyses demonstrate PRMT7-dependent methylation promotes Alba3 association with select target transcripts and thus indirectly stabilizes mRNA of a known virulence factor, δ-amastin surface antigen. These results highlight a novel role for PRMT7-mediated arginine methylation of RBP substrates, suggesting a regulatory pathway controlling gene expression and virulence in Leishmania. This work introduces Leishmania PRMTs as epigenetic regulators of mRNA metabolism with mechanistic insight into the functional manipulation of RBPs by methylation.

scholarly journals Arginine Methylation by PRMT1 Regulates Muscle Stem Cell Fate

2016 ◽  
Vol 37 (3) ◽  
Author(s):  
Roméo Sébastien Blanc ◽  
Gillian Vogel ◽  
Xing Li ◽  
Zhenbao Yu ◽  
Shawn Li ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Muscle Regeneration ◽  
Myogenic Differentiation ◽  
Arginine Methylation ◽  
Muscle Stem Cell ◽  
Stem Cell Fate ◽  
Protein Arginine Methyltransferase 1

ABSTRACT Quiescent muscle stem cells (MSCs) become activated in response to skeletal muscle injury to initiate regeneration. Activated MSCs proliferate and differentiate to repair damaged fibers or self-renew to maintain the pool and ensure future regeneration. The balance between self-renewal, proliferation, and differentiation is a tightly regulated process controlled by a genetic cascade involving determinant transcription factors such as Pax7, Myf5, MyoD, and MyoG. Recently, there have been several reports about the role of arginine methylation as a requirement for epigenetically mediated control of muscle regeneration. Here we report that the protein arginine methyltransferase 1 (PRMT1) is expressed in MSCs and that conditional ablation of PRMT1 in MSCs using Pax7CreERT2 causes impairment of muscle regeneration. Importantly, PRMT1-deficient MSCs have enhanced cell proliferation after injury but are unable to terminate the myogenic differentiation program, leading to regeneration failure. We identify the coactivator of Six1, Eya1, as a substrate of PRMT1. We show that PRMT1 methylates Eya1 in vitro and that loss of PRMT1 function in vivo prevents Eya1 methylation. Moreover, we observe that PRMT1-deficient MSCs have reduced expression of Eya1/Six1 target MyoD due to disruption of Eya1 recruitment at the MyoD promoter and subsequent Eya1-mediated coactivation. These findings suggest that arginine methylation by PRMT1 regulates muscle stem cell fate through the Eya1/Six1/MyoD axis.

scholarly journals Induction and Utilization of an ATM Signaling Pathway by Polyomavirus

2005 ◽  
Vol 79 (20) ◽  
pp. 13007-13017 ◽  
Author(s):  
Jean Dahl ◽  
John You ◽  
Thomas L. Benjamin
Keyword(s):  
Dna Repair ◽  
Protein A ◽  
S Phase ◽  
Productive Infection ◽  
Infected Cells ◽  
Cellular Dna ◽  
Atm Signaling Pathway ◽  
Atm Signaling

ABSTRACT Progression from G1 to S is essential for polyomavirus DNA replication and depends on the interaction of large T with the retinoblastoma gene product pRb. This virus-induced replication pathway is accompanied by p53 activation resembling a DNA damage response (12). We sought to determine whether this pathway depends in part on activation of the ATM (ataxia telangiectasia mutated) kinase and whether the virus gains advantages from this pathway beyond that of entry into S. We show that polyomavirus infection activates the S- and G2-phase checkpoints in primary as well as established mouse cells. Infected cells undergo a prolonged S phase compared to uninfected serum-stimulated cells and show no evidence of a G2→M transition before lytic death ensues. Infection is accompanied by increases in ATM activity in vitro and in the level of ATM-S1981-P in vivo. The incubation of infected cells with caffeine, a known ATM inhibitor, did not block entry into S but reduced the rate of viral compared to cellular DNA synthesis. Importantly, caffeine lowered the yields of viral DNA an average of 3- to 6-fold and those of infectious virus by as much as 10-fold. Virus yields were 10-fold lower in ATM −/− p53−/− than in ATM+/+ p53−/− mouse embryo fibroblasts, indicating a p53-independent role of ATM in productive infection. Replacement of the normal SMC1 (structural maintenance of chromosomes, or cohesin) protein, a critical ATM substrate in the DNA repair pathway, with its phosphorylation mutant SMC1S957AS966A also lowered virus yields by roughly 90%. We suggest that polyomavirus activates and utilizes a component(s) of an ATM pathway of DNA repair to prolong S phase and aid its own replication.

scholarly journals PRMT1 enhances oncogenic arginine methylation of NONO in colorectal cancer

Oncogene ◽  
2021 ◽  
Author(s):  
Xin-Ke Yin ◽  
Yun-Long Wang ◽  
Fei Wang ◽  
Wei-Xing Feng ◽  
Shao-Mei Bai ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Locally Advanced ◽  
Xenograft Model ◽  
Arginine Methylation ◽  
Mass Spectrometry Analysis ◽  
Migration And Invasion ◽  
Poor Overall Survival ◽  
Potential Marker

AbstractArginine methylation is an important posttranslational modification catalyzed by protein arginine methyltransferases (PRMTs). However, the role of PRMTs in colorectal cancer (CRC) progression is not well understood. Here we report that non-POU domain-containing octamer-binding protein (NONO) is overexpressed in CRC tissue and is a potential marker for poor prognosis in CRC patients. NONO silencing resulted in decreased proliferation, migration, and invasion of CRC cells, whereas overexpression had the opposite effect. In a xenograft model, tumors derived from NONO-deficient CRC cells were smaller than those derived from wild-type (WT) cells, and PRMT1 inhibition blocked CRC xenograft progression. A mass spectrometry analysis indicated that NONO is a substrate of PRMT1. R251 of NONO was asymmetrically dimethylated by PRMT1 in vitro and in vivo. Compared to NONO WT cells, NONO R251K mutant-expressing CRC cells showed reduced proliferation, migration, and invasion, and PRMT1 knockdown or pharmacological inhibition abrogated the malignant phenotype associated with NONO asymmetric dimethylation in both KRAS WT and mutant CRC cells. Compared to adjacent normal tissue, PRMT1 was highly expressed in the CRC zone in clinical specimens, which was correlated with poor overall survival in patients with locally advanced CRC. These results demonstrate that PRMT1-mediated methylation of NONO at R251 promotes CRC growth and metastasis, and suggest that PRMT1 inhibition may be an effective therapeutic strategy for CRC treatment regardless of KRAS mutation status.

scholarly journals A cloned cell line mediating natural killer cell function inhibits immunoglobulin secretion.

1982 ◽  
Vol 156 (2) ◽  
pp. 658-663 ◽  
Author(s):  
G Nabel ◽  
W J Allard ◽  
H Cantor
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Cell Line ◽  
B Lymphocytes ◽  
Cell Function ◽  
Killer Cell ◽  
Major Histocompatibility Complex Gene ◽  
Cell Surface Antigens

We previously described a cloned cell line that combines information for a unique display of cell surface antigens and specialized function similar to activated natural killer (NK) cells. In addition to conventional cellular targets such as the YAC-1 and MBL-2 lymphomas, this cloned line also lysed lipopolysaccharide-activated B lymphocytes. To determine whether some NK cells can inhibit B cell function, we tested the ability of NK-like clones to suppress Ig secretion in vitro and in vivo. These cloned cells suppressed Ig secretion when they constituted as few as 0.2% of the total cell population and inhibition did not require identity at the H-2 locus. We suggest that some NK cells might recognize non-major histocompatibility complex gene products on activated B lymphocytes and lyse these cells, and this might represent a fundamental cell-cell interaction that regulates antibody secretion by activated B cells.

Studies of two temperature-sensitive mutants of Mengo virus

1979 ◽  
Vol 57 (6) ◽  
pp. 902-913 ◽  
Author(s):  
Patrick W. K. Lee ◽  
John S. Colter
Keyword(s):  
Rna Synthesis ◽  
Viral Rna ◽  
Temperature Sensitive ◽  
Supporting Evidence ◽  
Structural Polypeptide ◽  
Infected Cells ◽  
Mengo Virus ◽  
In Vitro Stability

Studies of the synthesis of viral ribonucleates and polypeptides in cells infected with two RNA−ts mutants of Mengo virus (ts 135 and ts 520) have shown that when ts 135 infected cells are shifted from the permissive (33 °C) to the nonpermissive (39 °C) temperature: (i) the synthesis of all three species of viral RNA (single stranded, replicative form, and replicative intermediate) is inhibited to about the same extent, and (ii) the posttranslational cleavage of structural polypeptide precursors A and B is partially blocked. Investigations of the in vivo and in vitro stability of the viral RNA replicase suggest that the RNA− phentotype reflects a temperature-sensitive defect in the enzyme. The second defect does not appear to result from the inhibition of viral RNA synthesis at 39 °C, since normal cleavage of polypeptides A and B occurs in wt Mengo-infected cells in which viral RNA synthesis is blocked by cordycepin, and at the nonpermissive temperature in ts 520 infected cells. Considered in toto, the evidence suggests that ts 135 is a double mutant.Subviral (53 S) particles have been shown to accumulate in ts 520 (but not ts 135) infected cells when cultures are shifted from 33 to 39 °C. This observation provides supporting evidence for the proposal that this recently discovered particle is an intermediate in the assembly pathway of Mengo virions.

scholarly journals Analysis of the Interaction of the Adenovirus L1 52/55-Kilodalton and IVa2 Proteins with the Packaging Sequence In Vivo and In Vitro

2005 ◽  
Vol 79 (4) ◽  
pp. 2366-2374 ◽  
Author(s):  
Pilar Perez-Romero ◽  
Ryan E. Tyler ◽  
Johanna R. Abend ◽  
Monica Dus ◽  
Michael J. Imperiale
Keyword(s):  
Viral Protein ◽  
Direct Interaction ◽  
Dna Interaction ◽  
The Other ◽  
Infected Cells ◽  
In Vitro Interaction ◽  
Packaging Sequence

ABSTRACT We previously showed that the adenovirus IVa2 and L1 52/55-kDa proteins interact in infected cells and the IVa2 protein is part of two virus-specific complexes (x and y) formed in vitro with repeated elements of the packaging sequence called the A1-A2 repeats. Here we demonstrate that both the IVa2 and L1 52/55-kDa proteins bind in vivo to the packaging sequence and that each protein-DNA interaction is independent of the other. There is a strong and direct interaction of the IVa2 protein with DNA in vitro. This interaction is observed when probes containing the A1-A2 or A4-A5 repeats are used, but it is not found by using an A5-A6 probe. Furthermore, we show that complex x is likely a heterodimer of IVa2 and an unknown viral protein, while complex y is a monomer or multimer of IVa2. No in vitro interaction of purified L1 52/55-kDa protein with the packaging sequence was found, suggesting that the L1 52/55-kDa protein-DNA interaction may be mediated by an intermediate protein. Results support roles for both the L1 52/55-kDa and IVa2 proteins in DNA encapsidation.

Detection of Circulating Immune Complexes in the Sera of Rabbits with Experimental Syphilis: Possible Role in Immunoregulation

1980 ◽  
Vol 29 (2) ◽  
pp. 575-582
Author(s):  
Robert E. Baughn ◽  
Kenneth S. K. Tung ◽  
Daniel M. Musher
Keyword(s):  
Immune Complexes ◽  
Proteolytic Enzymes ◽  
Suppressor Cell ◽  
Suppressive Effect ◽  
Circulating Immune Complexes ◽  
Time Period ◽  
Infected Cells ◽  
Disseminated Disease

The in vivo and in vitro immunoglobulin G plaque-forming cell responses to sheep erythrocytes (SRBC) are nearly obliterated during disseminated syphilitic infection (3 to 8 weeks post-intravenous injection) in rabbits. Splenic and lymph node cells obtained from infected rabbits during this time period were capable of suppressing the normal in vitro responses of uninfected, SRBC-primed cells. Cell-free washings of cells from infected animals were also suppressive. This finding coupled with the fact that treatment of infected cells with proteolytic enzymes abrogated the suppressive effect constitute arguments against involvement of a specific suppressor cell population. The incidence of elevated levels of circulating immune complexes in the sera of rabbits with disseminated disease was also significantly different from that of uninfected controls or infected rabbits before the onset or after the regression of lesions. When added to cultures of lymphocytes from uninfected, SRBC-sensitized rabbits, sera containing complexes caused dose-related suppression of the in vitro immunoglobulin responses. Unlike immune complexes, no correlation was found between the presence of mucopolysaccharide materials and the stage of infection or the ability of serum to suppress the immunoglobulin responses to SRBC.

Identification of the immunophilins capable of mediating inhibition of signal transduction by cyclosporin A and FK506: roles of calcineurin binding and cellular location

1993 ◽  
Vol 13 (8) ◽  
pp. 4760-4769
Author(s):  
R J Bram ◽  
D T Hung ◽  
P K Martin ◽  
S L Schreiber ◽  
G R Crabtree
Keyword(s):  
Signal Transduction ◽  
T Cell ◽  
Cyclosporin A ◽  
Cell Function ◽  
Inhibitory Effects ◽  
Gene Deletions ◽  
Cyclophilin B ◽  
Intracellular Vesicles

The immunosuppressants cyclosporin A (CsA) and FK506 appear to block T-cell function by inhibiting the calcium-regulated phosphatase calcineurin. While multiple distinct intracellular receptors for these drugs (cyclophilins and FKBPs, collectively immunophilins) have been characterized, the functionally active ones have not been discerned. We found that overexpression of cyclophilin A or B or FKBP12 increased T-cell sensitivity to CsA or FK506, respectively, demonstrating that they are able to mediate the inhibitory effects of their respective immunosuppressants in vivo. In contrast, cyclophilin C, FKBP13, and FKBP25 had no effect. Direct comparison of the Ki of each drug-immunophilin complex for calcineurin in vitro revealed that although calcineurin binding was clearly necessary, it was not sufficient to explain the in vivo activity of the immunophilin. Subcellular localization was shown also to play a role, since gene deletions of cyclophilins B and C which changed their intracellular locations altered their activities significantly. Cyclophilin B has been shown previously to be located within calcium-containing intracellular vesicles; its ability to mediate CsA inhibition implies that certain components of the signal transduction machinery are also spatially restricted within the cell.

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