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Secondary product glycosyltransferases in seeds of Brassica napus.

This study describes a systematic screen for secondary product UDP-glycosyltransferases (UGTs; EC 2.4.1) involved in seed development of oilseed rape (Brassica napus) and was aimed at identifying genes related to UGT84A9 encoding UDP-glucose:sinapate glucosyltransferase (EC 2.4.1.120), a proven target for molecular breeding approaches to reduce the content of anti-nutritive sinapate esters. By RT-PCR with primers recognizing the conserved signature motif of UGTs, 13 distinct ESTs could be generated from seed RNA. Sequence analysis allowed to assign the isolated ESTs to groups B, D, E, and L of the UGT family. In an alternative approach, two open reading frames related to UGT84A9 were cloned from the B. napus genome and designated as UGT84A10 and UGT84A11, respectively. Functional expression of UGT84A10 revealed that the encoded enzyme catalyzes the formation of 1-O-acylglucosides (beta-acetal esters) with several hydroxycinnamates whereas, in our hands, the recombinant UGT84A11 did not display this enzymatic activity. Semi-quantitative RT-PCR confirmed that the majority of potential UGTs specified by the isolated ESTs is differentially expressed. A pronounced transcriptional up-regulation during seed development was evident for UGT84A9 and one EST (BnGT3) clustering in group E of UGTs. UGT84A10 was highly induced in flowers and expressed to a moderate level in late seed maturation indicating a possible involvement in seed-specific sinapate ester biosynthesis.

Amino Acid Sequence↗

Determinants of pantropism of the F1-R mutant of Sendai virus: specific mutations involved are in the F and M genes.

Mutations in the fusion, F, protein of Sendai virus resulting in increased cleavability by ubiquitous host protease(s), and mutations in the matrix, M, protein resulting in bipolar budding, are both important determinants for the systemic infection in mice caused by the protease activating pantropic mutant, F1-R. Several mutants of Sendai virus (BY, BF, and KD-M) with phenotypes of bipolar budding and/or increased cleavability of F protein were isolated. Genomic RNA sequence analysis of the F and M genes of the mutants revealed that several deduced amino acids in the F and M proteins were different from those of F1-R, T-5 (a revertant of F1-R), and wild-type viruses. The BF and KD-M mutants that budded bipolarly and were also activated by ubiquitous proteases were examined for replication in tissue culture cells and in mice. All of the mutants exhibited multiple-step replication in MDCK, MDBK, and LLC-MK2 cells without trypsin, but formed plaques only in MDCK cells. One of the mutants, designated KD-52M, was similar to F1-R in that it formed plaques in all three cell lines without addition of exogenous protease. However, none of the mutants viruses, including KD-52M, caused a systemic infection in mice. The mutated M protein of F1-R enhances the disruption of microtubles. However, none of the mutants with a bipolar budding phenotype (BY, BF, and KD-M), disrupted the microtubules to the same extent as F1-R. All of these mutants had mutations in the M protein that were different from those found in F1-R. Taken together, these results suggest that mutations at Ser115 to Pro in the F protein and at Asp 128 to Gly and Ile210 to Thr in the M protein of F1-R are the mutations specifically required for the systemic infection caused by F1-R.

Amino Acid Sequence↗

C6ORF120 regulates hepatic lipid metabolism through PPAR signaling pathway in metabolic dysfunction-associated steatotic liver disease.

Background Emerging evidence indicates that C6ORF120 is highly expressed in the liver and may modulate immune responses in various hepatic disorders. However, its role in hepatic lipid metabolism and metabolic dysfunction-associated steatotic liver disease (MASLD) is unexplored. This study aimed to elucidate the effects and potential mechanisms of C6ORF120 on hepatic lipogenesis. Methods C6ORF120 expression in MASLD was assessed using patient serum and the Gene Expression Omnibus (GEO) database. A high-fat diet-induced MASLD model was established in C6orf120-KO rats. Fatty acid-induced lipid accumulation models were generated in primary hepatocytes, HepG2 and Huh7 cells. These models were employed to investigate the effects of C6ORF120 on hepatic lipogenesis and MASLD progression. Results C6ORF120 expression was significantly upregulated in MASLD patients and obese rat models. Genetic deletion of C6ORF120 markedly alleviated high-fat diet-induced steatosis in the liver of rats. In vitro, C6orf120 gene deficiency attenuated lipid accumulation and suppressed key lipogenic genes (such as fatty acid synthase (Fasn), phospho-acetyl coenzyme carboxylase (p-ACC), sterol regulatory element binding protein-1c (Srebp1c)) in primary hepatocytes and HepG2 cells. Conversely, C6ORF120 overexpression increased lipid accumulation in HepG2 cells. RNA sequencing analysis showed that lipid metabolism pathway and peroxisome proliferators activated receptor (PPAR) signaling pathway were significantly altered in the liver of C6orf120-KO rats. We demonstrated that C6ORF120 may regulate lipid metabolism through the hepatic PPARα, which is involved in fatty acid production and lipid oxidation. Further, we found that serum C6ORF120 expression was correlated with clinical indicators in patients with MASLD. Conclusion This study preliminarily revealed a novel function for C6ORF120 in hepatic lipid metabolism via affecting the PPAR pathway. The result identifies C6ORF120 as a novel regulator of hepatic lipid metabolism through PPARα-dependent mechanisms, offering potential therapeutic targets for MASLD.

Lipid Metabolism↗

Molecular genetic evidence of bacterial colonization of cholesterol gallstones.

BACKGROUND/AIMS: Cholesterol gallstone formation is believed to be unrelated to the presence of bacteria because attempts to culture potentially causative bacteria from surgically removed cholesterol stones have failed. However, the formation of gallbladder gallstones takes years. Embedded bacteria may be damaged or killed. The aim of this study was to search for bacterial DNA sequences in cholesterol stones with negative bacterial culture. METHODS: Bacterial gene fragments were amplified in vitro from DNA extracted from cholesterol gallbladder stones. Comparative 16S ribosomal RNA sequence analysis was used for identification. RESULTS: Gallstones with cholesterol content between 70% to 90% harbored bacterial DNA (16 of 17 patients). No bacterial DNA was found in the gallstones with cholesterol content of > 90% (3 patients). Three bacterial groups typical for gallstone colonization were identified. Propionibacteria-related DNA was found in the stones of 9 patients (45%). Enterobacterial type sequences were obtained in 5 patients (25%). A more heterogenous sequence collection was retrieved from 7 patients (35%) and could be assigned to the major bacterial line of gram-positive bacteria with a low DNA guanine and cytosine content. CONCLUSIONS: Most cholesterol gallstones harbor bacterial DNA. It is important to determine the actual role of these microorganisms in gallstone formation.

Adult↗

A proflavin-induced frameshift hotspot in the thymidylate synthase gene of bacteriophage T4.

Twenty-one independent thymidylate synthase deficient (td) mutants were isolated after proflavin mutagenesis of T4D0 phage. A strikingly high proportion of these mutations (17 of 21; 80%) mapped in a small 122 nucleotide (nt) region which spans the 5' splice site of this intron-containing gene. This region comprises only 14% of the total td exon sequence. RNA sequence analysis of these mutants identified a series of frameshift insertion/deletion mutations and indicated a hotspot for proflavin-induced mutations in the 3' end of exon I of the td gene. The mutant sequences at the hotspot site fully support a previously proposed mutagenic mechanism for proflavin-induced mutations in which frameshifts are produced as a consequence of exonuclease or DNA polymerase activity at the 3' ends of nicks in the DNA produced by perturbation of the T4-encoded type II topoisomerase activity by the acridine. Sixteen of the seventeen DNA mutations in the hotspot region can be explained by the model as a consequence of enzymatic processing of nicks at two phosphodiester bonds staggered by 4 base pairs (bp) and located on opposite strands of the DNA. Thus, these mutants exhibit precisely the symmetry expected of topoisomerase-mediated mutagenesis. The DNA sequences of the td hotspot mutants, when considered with the sequences of proflavin-induced mutants in the T4 rIIB and lysozyme genes, confirm the view that proflavin-induced mutations in diverse bacteriophage T4 DNA sequences are all produced by the topoisomerase-dependent mechanisms and do not support the view that classical misalignments in DNA repeats are hotspots for proflavin-induced mutagenesis in T4.

Bacteriophage T4↗

Neutralizing epitopes of lymphocytic choriomeningitis virus are conformational and require both glycosylation and disulfide bonds for expression.

Lymphocytic choriomeningitis virus (Armstrong strain) bears two overlapping epitopes, GP-1A (A) and GP-1D (D), recognized by neutralizing antibodies on the major surface glycoprotein GP-1. Both are discontinuous conformational epitopes that require prior formation of disulfide bridges and addition of N-linked oligosaccharides. Using monoclonal antibodies specific for each of these epitopes, as well as for conformation-independent epitopes, we have investigated the requirements for biosynthesis and folding of the epitopes. The carbohydrate residues themselves do not appear to comprise critical informational components of these epitopes, but are required for proper folding of the nascent glycopeptide chain within the rough endoplasmic reticulum. These epitopes differ in their resistance to denaturation; epitope D is retained when denatured with SDS under nonreducing conditions, whereas epitope A is lost. Monoclonal antibodies to epitope A cross-react with several strains of LCMV. However, epitope D is detected in only a subset of isolates derived from the Armstrong strain of LCMV. By RNA sequence analysis, we have mapped a single amino acid change distinguishing those virions containing epitope D. Acquisition of binding activity of the epitope D-specific monoclonal correlates with a Thr----Ala or Thr----Lys mutation at amino acid 173 of the GP-1 molecule and concomitant disruption of a consensus N-linked glycosylation site.

Amino Acid Sequence↗

Pneumotropic revertants derived from a pantropic mutant, F1-R, of Sendai virus.

Revertants were isolated from the protease activation mutant of Sendai virus, F1-R, which causes a systemic infection in mice. The fusion (F) glycoprotein of F1-R is susceptible to activation cleavage by ubiquitous cellular proteases and is thus responsible for pantropism in mice (Tashiro et al., 1988. Virology 165, 577-583). The revertants regained several phenotypes of wild-type virus; they required exogenous trypsin for activation of the F protein in cell cultures and in nonpulmonary mouse tissues and they were exclusively pneumotropic in mice. On the other hand, phenotypes of F1-R that remained unchanged by the revertants were bipolar budding in polarized epithelial cells, enhanced electrophoretic migration of the matrix protein, and the lack of a glycosylation site in the F2 subunit of the F protein. Comparative RNA sequence analysis of the F gene of the revertants revealed that the reduced cleavability of the F protein of the revertants was the result of the predicted single amino acid reversion (Pro to Ser) at residue 115 adjacent to the cleavage site. Thus the sequence at the cleavage site of the revertants was Ser-Lys compared with Pro-Lys for F1-R and Ser-Arg for wild-type virus. The results indicate that enhanced cleavability of the glycoprotein, a feature often associated with multiple basic residues within the cleavage site of paramyxovirus F proteins and influenza virus hemagglutinins, can also be determined by a single basic amino acid following proline. Additionally, the revertants were less susceptible to the activator for wild-type virus present in mouse lungs and less pathogenic for this organ than wild-type virus. These results provide further evidence that proteolytic activation of the F protein by host proteases is the primary determinant for organ tropism and pathogenicity of Sendai virus in mice. One of the revertants was also temperature sensitive (ts); the ts lesion in the nucleoprotein gene was identical to that found in ts-f1, the ts host range mutant from which F1-R was derived.

Amino Acid Sequence↗

Differential display of hepatic mRNA from killifish (Fundulus heteroclitus) inhabiting a Superfund estuary.

Fundulus heteroclitus (Atlantic killifish, mummichog) from a highly contaminated site on the Elizabeth River (VA, USA) are resistant to the toxicity of sediment from the site. However, the mechanistic changes that confer resistance to the toxicity are not yet well understood. We utilized differential display to identify mRNAs that are differentially expressed in hepatic tissue of male and female killifish from the Elizabeth River environment, compared to killifish from a non-contaminated reference site, King's Creek (VA, USA). Seventy-four differentially expressed mRNAs were initially identified (including sex and population-specific differences), and 65 of these were isolated and sequenced. A reverse northern blot array constructed of these cDNAs (plus an additional 15 previously sequenced mRNAs of interest) was used to confirm and quantify expression differences. High interindividual variability was observed in mRNA expression, but multiple differentially expressed mRNAs were identified, including 11 population-specific differences occurring in both sexes, 24 population-specific differences occurring in only one sex, and 22 sex-specific differences. Many of these differentially expressed mRNAs were novel, or not previously hypothesized to play a role in response to contaminant exposure. In addition, the results indicate that the effect of contaminated sediment exposure on the expression of a large proportion of the differentially expressed mRNAs was dependent on the sex of the fish.

Analysis of Variance↗

A test of Chargaff's second rule.

In 1968, Chargaff and his colleagues discovered a rule in Bacillus subtilis: in single stranded DNA, A=T and C=G. This rule has since been confirmed many times in other bacterial and eukaryotic genomes. To the best of our knowledge, this rule has not been tested before in either single stranded DNA or RNA genomes. Over 3400 genomic sequences were examined here and included for the first time both double and single stranded DNA and RNA genomes. We found that: (1) with the exception of the organellar DNA, this parity rule holds for all types of double stranded DNA genomes and (2) that this rule fails to hold for other types of genomes. The parity rule appears to be a selective force on genome evolution and codon use.

Archaea↗

Hcc-2, a novel mammalian ER thioredoxin that is differentially expressed in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver. Thus there is great interest to identify novel HCC diagnostic markers for early detection of the disease and tumour specific associated proteins as potential therapeutic targets in the treatment of HCC. Currently, we are screening for early biomarkers as well as studying the development of HCC by identifying the differentially expressed proteins of HCC tissues during different stages of disease progression. We have isolated, by reverse transcriptase and polymerase chain reaction (RT-PCR), a 1741bp cDNA encoding a protein that is differentially expressed in HCC. This novel protein was initially identified by proteome analysis and we designate it as Hcc-2. The protein is upregulated in poorly-differentiated HCC but unchanged in well-differentiated HCC. The full-length transcript encodes a protein of 363 amino acids that has three thioredoxin (Trx) (CGHC) domains and an ER retention signal motif (KDEL). Fluorescence GFP tagging to this protein confirmed that it is localized predominantly to the cytoplasm when expressed in mammalian cells. Protein alignment analysis shows that it is a variant of the TXNDC5 gene, and the human variants found in Genbank all show close similarity in protein sequence. Functionally, it exhibits the anticipated reductase activity in the insulin disulfide reduction assay, but its other biological role in cell function remains to be elucidated. This work demonstrates that an integrated proteomics and genomics approach can be a very powerful means of discovering potential diagnostic and therapeutic protein targets for cancer therapy.

Amino Acid Motifs↗

Revolutions in RNA secondary structure prediction.

RNA structure formation is hierarchical and, therefore, secondary structure, the sum of canonical base-pairs, can generally be predicted without knowledge of the three-dimensional structure. Secondary structure prediction algorithms evolved from predicting a single, lowest free energy structure to their current state where statistics can be determined from the thermodynamic ensemble. This article reviews the free energy minimization technique and the salient revolutions in the dynamic programming algorithm methods for secondary structure prediction. Emphasis is placed on highlighting the recently developed method, which statistically samples structures from the complete Boltzmann ensemble.

Algorithms↗

Maraviroc alleviates neuropathic pain symptoms in a mouse model of spared nerve injury.

Chronic pain represents a major health problem in the health care system. According to the CDC data brief in 2020, 20.4% of adults have chronic pain. There has been no promising therapy for chronic pain. Currently available treatments include medications such as nonsteroidal anti-inflammatory drugs, antiepileptic drugs, tricyclic antidepressants, corticosteroids, opioids, and cannabinoids, all of which may cause various negative side effects. Thus, there is an urgent need to develop novel, efficacious, and safe interventions for treating pain. Studies have shown that proinflammatory cytokines and chemokines make important contributions to the initiation and persistence of pain. We have found that C-C motif chemokine ligand 5 levels increased at day 14 post-spared nerve injury (SNI). This study was designed to investigate the effect of maraviroc (MVC), an FDA-approved CCR5 antagonist, on neuropathic pain in a mouse model of SNI. We found that MVC alleviated SNI-induced mechanical allodynia at 3, 7, and 14 days postinjury. MVC treatment also prevented SNI-mediated thermal hypersensitivity at 7 and 14 days postinjury in both male and female cohorts. SNI resulted in weight-bearing deficits, which were corrected by MVC administration in male mice. RNA sequencing analysis revealed that MVC rescued SNI-induced dysregulation of sex-specific canonical pathways in the spinal cord. Collectively, our findings showed that MVC could reduce neuropathic pain following peripheral nerve injury, providing a base for the repurposing of this FDA-approved human immunodeficiency virus drug as a pain reducer in clinical applications. SIGNIFICANCE STATEMENT: Spared nerve injury-induced neuropathic pain is associated with upregulation of the C-C motif chemokine ligand 5. Targeting the C-C motif chemokine ligand 5-CCR5 axis with FDA-approved maraviroc alleviated pain phenotype through modulating different pathways in male and female mice.

Animals↗

A DNA expression array to detect toxic stress response in European flounder (Platichthys flesus).

As a first stage in developing a DNA array-based approach to investigating the effects of pollutants on an environmentally relevant European fish species, we have constructed a 160-gene custom microarray for European flounder. Degenerate primers were used to amplify 110 different fragments of stress-related and other genes from European flounder cDNA and genomic DNA. Additionally, 22 fragments were obtained by suppressive subtractive hybridisation (SSH). These fragments were cloned and sequenced, then, with additional control genes, used to create a cDNA microarray for flounder. After optimisation of the arraying process, hepatic mRNA was isolated from flounder caught in the polluted Tyne and relatively unpolluted Alde estuaries. Fluorescent cDNA probes were synthesised from the mRNA and used in dual-colour hybridisations to the microarray. A number of transcripts were differentially expressed between Tyne and Alde female flounder but these changes were not significant, due to high inter-individual variation. However, in comparisons between Tyne and Alde male flounder, 11 transcripts were found to significantly differ in expression (P<0.05). Seven transcripts were more highly expressed in the Tyne male fish (CYP1A, UDPGT, alpha-2HS-glycoprotein, dihydropyrimidine dehydrogenase, Cu/Zn SOD, aldehyde dehydrogenase and paraoxonase). Four transcripts (Elongation factor 1 (EF1), EF2, Int-6 and complement component C3) were found to be significantly less abundant in the Tyne male fish. Selected genes were assayed by real-time PCR, then normalised to alpha-tubulin. These assays confirmed the significance of the array results for CYP1A, UDPGT and EF1, but not for Cu/Zn SOD. This study provides a link between traditional single-gene biomarker studies and the emerging field of eco-toxicogenomics, demonstrating the utility of microarray studies on environmentally sampled, non-model organisms.

Animals↗

Cloning and analysis of a transcript derived from two contiguous genes of the cathelicidin family.

Bac4 is a bovine cathelicidin gene contiguous to another member of this family named Bac7. Although mutations in the sequence suggested that Bac4 gene might be non-functional, primers based on Bac4 specific sequences allowed amplification of a 900 bp cDNA. The transcript comprises the sequences of exons 1, 2 and 3 of Bac7, and of exons 2, 3 and 4 of Bac4 gene and may result from a weak termination control of the transcription of the upstream Bac7 gene.

Amino Acid Sequence↗

Comparison of the complete genomic sequence of the border disease virus, BD31, to other pestiviruses.

The genus Pestivirus is composed of hog cholera virus (HCV) [also known as classical swine fever virus (CSFV)], bovine viral diarrhea virus (BVDV), and border disease virus (BDV). Complete sequences have been published for HCV (or CSFV) and the two genotypes of BVDV (BVDV1 and BVDV2). In this study the complete sequence of the border disease virus (BDV), BD31, was determined. BD31 was isolated from a lamb with hairy shaker syndrome and is the BDV type virus offered by ATCC (ATCC VR-996). The genome was 12268 nucleotides long and had a single large open reading frame (ORF) beginning at nucleotide 357 and ending at nucleotide 12045. The sequence identity of the predicted amino acid sequence of BD31 and other published pestivirus sequences varied from 71% to 78%. Phylogenetic analysis of available complete genomic sequences segregated pestiviruses into two branches. One branch contained BD31 and HCV (or CSFV) isolates while the other branch contained BVDV1 and BVDV2 isolates. Pestiviruses from the same branch were similar in the length of the 5' and 3' untranslated regions (UTR). When complete genomic sequences were compared among BD31, HCV (or CSFV), BVDV1 and BVDV2, the highest sequence identity was observed in the 5' UTR. Within the ORF, the highest sequence identity was observed in the genomic region coding for the nonstructural viral polypeptide p80.

Amino Acid Sequence↗

Shotgun sequencing and microarray analysis of RDA transcripts.

Monitoring of differential gene expression is an important step towards understanding of gene function. We describe a comparison of the representational difference analysis (RDA) subtraction process with corresponding microarray analysis. The subtraction steps are followed in a quantitative manner using a shotgun cloning and sequencing procedure that includes over 1900 gene sequences. In parallel, the enriched transcripts are spotted onto microarrays facilitating large scale hybridization analysis of the representations and the difference products. We show by the shotgun procedure that there is a high diversity of gene fragments represented in the iterative RDA products (92-67% singletons) with a low number of shared sequences (<9%) between subsequent subtraction cycles. A non redundant set of 1141 RDA clones were immobilized on glass slides and the majority of these clones (97%) gave repeated good fluorescent signals in a subsequent hybridization of the labelled and amplified original cDNA. We observed only a low number of false positives (<2%) and a more than twofold differential expression for 32% (363) of the immobilized RDA clones. In conclusion, we show that by random sequencing of the difference products we obtained an accurate transcript profile of the individual steps and that large-scale confirmation of the obtained transcripts can be achieved by microarray analysis.

Cell Line↗

Aptamers that bind to the antibiotic moenomycin A.

Nuclease-resistant moenomycin-binding aptamers with dissociation constants in the range of 300 to 400 nM have been selected. Competition experiments have demonstrated that these aptamers recognize a disaccharide analogue of moenomycin. The results offer the opportunity of setting up a selective and sensitive assay for identifying moenomycin biosynthetic precursors.

Anti-Bacterial Agents↗