Characterization of the proteins encoded by a recently emerged cotton-infecting Polerovirus.

The cotton leafroll dwarf virus (CLDV), an important viral pathogen responsible for substantial losses in cotton crops, has recently emerged in the United States (US). Although CLDV shares similarities with other members of the genus Polerovirus in terms of encoded proteins, their functional characteristics remain largely unexplored. In this study, we expressed and analyzed each protein encoded by CLDV to determine its intracellular localization using fluorescence protein fusion.

The Intriguing Conundrum of a Nonconserved Multifunctional Protein of Citrus Tristeza Virus That Interacts with a Viral Long Non-Coding RNA.

(CTV), the largest non-segmented plant RNA virus, has several peculiar features, among which is the production of a 5'-terminal long non-coding RNA (lncRNA) termed low-molecular-weight tristeza 1 (LMT1). In this study, we found that p33, a unique viral protein that performs multiple functions in the virus infection cycle, specifically binds LMT1, both in vivo and in vitro. These results were obtained through the expression of p33 under the context of the wild type virus infection or along with a mutant CTV variant that does not produce LMT1 as well as via ectopic co-expression of p33 with LMT1 in leaves followed by RNA immunoprecipitation and rapid amplification of cDNA ends assays.

A Non-Conserved p33 Protein of Citrus Tristeza Virus Interacts with Multiple Viral Partners.

The RNA genome of citrus tristeza virus (CTV), one of the most damaging viral pathogens of citrus, contains 12 open reading frames resulting in production of at least 19 proteins. Previous studies on the intraviral interactome of CTV revealed self-interaction of the viral RNA-dependent RNA polymerase, the major coat protein (CP), p20, p23, and p33 proteins, while heterologous interactions between the CTV proteins have not been characterized. In this work, we examined interactions between the p33 protein, a nonconserved protein of CTV, which performs multiple functions in the virus infection cycle and is needed for virus ability to infect the extended host range, with other CTV proteins shown to mediate virus interactions with its plant hosts.

A Long Non-Coding RNA of : Role in the Virus Interplay with the Host Immunity.

During infection, (CTV) produces a non-coding subgenomic RNA referred to as low-molecular-weight tristeza 1 (LMT1), which for a long time has been considered as a by-product of the complex CTV replication machinery. In this study, we investigated the role of LMT1 in the virus infection cycle using a CTV variant that does not produce LMT1 (CTV-LMT1d). We showed that lack of LMT1 did not halt virus ability to replicate or form proper virions.

Functional diversification upon leader protease domain duplication in the Citrus tristeza virus genome: Role of RNA sequences and the encoded proteins.

Viruses from the family Closteroviridae show an example of intra-genome duplications of more than one gene. In addition to the hallmark coat protein gene duplication, several members possess a tandem duplication of papain-like leader proteases. In this study, we demonstrate that domains encoding the L1 and L2 proteases in the Citrus tristeza virus genome underwent a significant functional divergence at the RNA and protein levels.

Cytomegalovirus Gastric Ulcer Complicated with Pyloric Obstruction in a Patient with Ulcerative Colitis.

In patients with inflammatory bowel disease (IBD), cytomegalovirus (CMV) infections could aggravate the course of IBD but it is difficult to distinguish CMV infection from IBD exacerbation endoscopically. Usually, CMV tends to localize to the colon and other organic involvements were reported very rare in the IBD patients. Herein, we report a case that CMV gastric ulcer complicated with pyloric obstruction in a patient with ulcerative colitis during ganciclovir therapy, which was resolved by surgical gastrojejunostomy with review of literature.

Self-interaction of Citrus tristeza virus p33 protein via N-terminal helix.

Citrus tristeza virus (CTV), the most economically important viral pathogen of citrus, encodes a unique protein, p33. CTV p33 shows no similarity with other known proteins, yet plays an important role in viral pathogenesis: it extends the virus host range and mediates virus ability to exclude superinfection by other variants of the virus. Previously we demonstrated that p33 is an integral membrane protein and appears to share characteristics of viral movement proteins.

Understanding superinfection exclusion by complex populations of Citrus tristeza virus.

Superinfection exclusion (SIE) is a phenomenon in which a primary viral infection restricts a secondary infection with the same or closely related virus. Previously we showed that SIE by Citrus tristeza virus (CTV) occurs only between isolates of the same virus genotype. This work, however, was done using single genotype-containing isolates, while most field citrus trees harbor complex populations composed of different virus genotypes.

A 5'-proximal region of the Citrus tristeza virus genome encoding two leader proteases is involved in virus superinfection exclusion.

Superinfection exclusion (SIE), a phenomenon in which a primary virus infection prevents a secondary infection with the same or closely related virus, has been observed with various viruses. Earlier we demonstrated that SIE by Citrus tristeza virus (CTV) requires viral p33 protein. In this work we show that p33 alone is not sufficient for virus exclusion.

A nuclear fraction of turnip crinkle virus capsid protein is important for elicitation of the host resistance response.

The N-terminal 25 amino acids (AAs) of turnip crinkle virus (TCV) capsid protein (CP) are recognized by the resistance protein HRT to trigger a hypersensitive response (HR) and systemic resistance to TCV infection. This same region of TCV CP also contains a motif that interacts with the transcription factor TIP, as well as a nuclear localization signal (NLS). However, it is not yet known whether nuclear localization of TCV CP is needed for the induction of HRT-mediated HR and resistance.

Membrane association of a nonconserved viral protein confers virus ability to extend its host range.

Citrus tristeza virus (CTV), the largest and most complex member of the family Closteroviridae, encodes a unique protein, p33, which shows no homology with other known proteins, however, plays an important role in virus pathogenesis. In this study, we examined some of the characteristics of p33. We show that p33 is a membrane-associated protein that is inserted into the membrane via a transmembrane helix formed by hydrophobic amino acid residues at the C-terminal end of the protein.

A spectrum of HRT-dependent hypersensitive responses elicited by the 52 amino acid N-terminus of turnip crinkle virus capsid protein and its mutants.

The capsid protein (CP) of turnip crinkle virus (TCV) is the elicitor of hypersensitive response (HR) and resistance mediated by the resistance protein HRT in the Di-17 ecotype of Arabidopsis. Here we identified the N-terminal 52-amino-acid R domain of TCV CP as the elicitor of HRT-dependent HR in Nicotiana benthamiana. Mutating this domain at position 6 (R6A), but not at positions 8 (R8A) or 14 (G14A), abolished HR in N.

Modification of ASC1 by UFM1 is crucial for ERα transactivation and breast cancer development.

Biological roles for UFM1, a ubiquitin-like protein, are largely unknown, and therefore we screened for targets of ufmylation. Here we show that ufmylation of the nuclear receptor coactivator ASC1 is a key step for ERα transactivation in response to 17β-estradiol (E2). In the absence of E2, the UFM1-specific protease UfSP2 was bound to ASC1, which maintains ASC1 in a nonufmylated state.

The charged residues in the surface-exposed C-terminus of the Soybean mosaic virus coat protein are critical for cell-to-cell movement.

The Soybean mosaic virus (SMV) coat protein (CP) is necessary for virion assembly and viral cell-to-cell and long-distance movements in plants. We previously showed that the C-terminal region of the SMV CP is required for CP self-interaction. In the present study, we generated SMV mutants containing CPs with single amino acid substitutions of the charged amino acids in the C-proximal region.

SUMOylation of hnRNP-K is required for p53-mediated cell-cycle arrest in response to DNA damage.

Heterogeneous ribonucleoprotein-K (hnRNP-K) is normally ubiquitinated by HDM2 for proteasome-mediated degradation. Under DNA-damage conditions, hnRNP-K is transiently stabilized and serves as a transcriptional co-activator of p53 for cell-cycle arrest. However, how the stability and function of hnRNP-K is regulated remained unknown.

Mutational analysis of interaction between coat protein and helper component-proteinase of Soybean mosaic virus involved in aphid transmission.

Soybean mosaic virus (SMV), a member of the genus Potyvirus, is transmitted by aphids in a non-persistent manner. It has been well documented that the helper component-proteinase (HC-Pro) plays a role as a 'bridge' between virion particles and aphid stylets in the aphid transmission of potyviruses. Several motifs, including the KITC and PTK motifs on HC-Pro and the DAG motif on the coat protein (CP), have been found to be involved in aphid transmission.

A novel type of E3 ligase for the Ufm1 conjugation system.

The ubiquitin fold modifier 1 (Ufm1) is the most recently discovered ubiquitin-like modifier whose conjugation (ufmylation) system is conserved in multicellular organisms. Ufm1 is known to covalently attach with cellular protein(s) via a specific E1-activating enzyme (Uba5) and an E2-conjugating enzyme (Ufc1), but its E3-ligating enzyme(s) as well as the target protein(s) remain unknown. Herein, we report both a novel E3 ligase for Ufm1, designated Ufl1, and an Ufm1-specific substrate ligated by Ufl1, C20orf116.

Dual modification of BMAL1 by SUMO2/3 and ubiquitin promotes circadian activation of the CLOCK/BMAL1 complex.

Heterodimers of BMAL1 and CLOCK drive rhythmic expression of clock-controlled genes, thereby generating circadian physiology and behavior. Posttranslational modifications of BMAL1 play a key role in modulating the transcriptional activity of the CLOCK/BMAL1 complex during the circadian cycle. Recently, we demonstrated that circadian activation of the heterodimeric transcription factor is accompanied by ubiquitin-dependent proteolysis of BMAL1.

[A case of anti-LKM 1 positive autoimmune hepatitis accompanied by systemic lupus erythematosus].

Overlap of autoimmune hepatitis and systemic lupus erythematosus (SLE) is a comparatively rare condition. Although both autoimmune hepatitis and SLE can share common autoimmune features such as polyarthralgia, hypergammaglobulinemia and positive ANA, it has been considered as two different entities. We report a case of anti-LKM1 positive autoimmune hepatitis who developed SLE two years later.

Structural basis for Ufm1 processing by UfSP1.

Ubiquitin-fold modifier 1 (Ufm1) is a newly identified ubiquitin-like protein. Like ubiquitin and other ubiquitin-like proteins, Ufm1 is synthesized as a precursor that needs to be processed to expose the conserved C-terminal glycine prior to its conjugation to target proteins. Two novel proteases, named UfSP1 and UfSP2, have been shown to be responsible for the release of Ufm1 from Ufm1-conjugated cellular proteins as well as for the processing of its precursor.

[A case of Diphyllobothrium latum infection in a patient with abdominal pain].

The growing popularity of eating raw fish has resulted in increase of certain human parasitic infection, such as diphyllobothriasis. Even though, upper and lower gastrointestinal endoscopy reveal no specific abnormality, if a patient complains of persistent abdominal pain, we should consider the possibility of parasitic infection. Careful history taking and stool examination can avoid further invasive study.

Two novel ubiquitin-fold modifier 1 (Ufm1)-specific proteases, UfSP1 and UfSP2.

Ubiquitin-fold modifier 1 (Ufm1) is a recently identified new ubiquitin-like protein, whose tertiary structure displays a striking resemblance to ubiquitin. Similar to ubiquitin, it has a Gly residue conserved across species at the C-terminal region with extensions of various amino acid sequences that need to be processed in vivo prior to conjugation to target proteins. Here we report the isolation, cloning, and characterization of two novel mouse Ufm1-specific proteases, named UfSP1 and UfSP2.

Importance of the C-terminal domain of soybean mosaic virus coat protein for subunit interactions.

The potyvirus coat protein (CP) is involved in aphid transmission, cell-to-cell movement and virus assembly, not only by binding to viral RNA, but also by self-interaction or interactions with other factors. In this study, a number of CP mutants of Soybean mosaic virus (SMV) containing deletions and site-directed mutations were generated and cloned into yeast two-hybrid vectors. Interaction was confirmed by the expression of reporter genes, including HIS3, ADE2 and MEL1, in yeast strain AH109.

Strategies for assaying deubiquitinating enzymes.

A general method for assaying deubiquitinating enzymes (DUBs) has been developed. This new method employs an indirect enzyme assay for determining the activity of DUBs using a linear fusion of polyHis-glutathione-S-transferase-ubiquitin-ecotin (His-GST-Ub-ecotin) as a substrate. Because ecotin, a trypsin inhibitor protein from Escherichia coli, is heat stable, the activity of DUBs can be assayed indirectly by determining the ability of ecotin to inhibit trypsin after incubation of any DUB with His-GST-Ub-ecotin followed by heating at 100 degrees.

A protein interaction map of soybean mosaic virus strain G7H based on the yeast two-hybrid system.

A protein interaction map of Soybean mosaic virus (SMV) strain G7H was generated by the yeast two-hybrid system. Clones encoding the genes P1, HC-Pro, P3, 6K1, CI, 6K2, VPg, NIa, NIb, and CP were fused downstream of the GAL4 binding domain (GAL4-BD) and of the GAL4 activation domain (GAL4-AD). The GAL4-BD and GAL4-AD fusion derivatives of each gene were co-transformed into yeast and transformants in which interaction took place were identified on selective media.