Project description:Chronic infections by hepatitis B virus (HBV) and hepatitis C virus (HCV) appear to be the most significant causes of hepatocellular carcinoma (HCC). Aberrant promoter methylation is known to be deeply involved in cancer, including HCC. In this study, we analyzed aberrant promoter methylation on genome-wide scale in 6 HCCs including 3 HBV-related and 3 HCV-related HCCs, 6 matched noncancerous liver tissues and 3 normal liver tissues by methylated DNA immunoprecipitation-on-chip analysis. Candidate genes with promoter methylation were detected more frequently in HCV-related HCC. Candidate genes methylated preferentially to HBV-related or HCV-related HCCs were detected and selected, and methylation levels of the selected genes were validated using 125 liver tissue samples, including 61 HCCs (28 HBV-related HCCs and 33 HCV-related HCCs) and matched 59 matched noncancerous livers, and 5 normal livers, by quantitative methylation analysis using MALDI-TOF mass spectrometry. Among analyzed genes, preferential methylation in HBV-related HCC was validated in 1 gene only. However, 15 genes were found methylated preferentially in HCV-related HCC, which was independent from age. Hierarchical clustering of HCC using these 15 genes stratified HCV-related HCC as a cluster of frequently methylated samples. The 15 genes included genes inhibitory to cancer-related signaling such as RAS/RAF/ERK and Wnt/b-catenin pathways. It was indicated that genes methylated preferentially in HCV-related HCC exist, and it was suggested that DNA methylation might play an important role in HCV-related HCC by silencing cancer-related pathway inhibitors. we analyzed aberrant promoter methylation in 6 HCC clinical samples (including 3 HBV-related HCCs and 3 HCV-related HCCs) and their matched noncancerous tissues on genome-wide scale by the method. Candidate regions of promoter methylation preferentially to HBV-related HCC and HCV-related HCC were selected, and the methylation levels of these genes were measured quantitatively using MALDI-TOF mass spectrometry. Expression levels of these 6 pairs of HCC and 4 more pairs of HCCs and surrounding noncancerous tissues were analyzed by expression array and are reported in this Series. <br><br>This experiment was reloaded in November 2010 after additional curation. this dataset is part of the TransQST collection.
Project description:Clinical Flavobacterium columnare ATCC 49512 was grown on Flavobacterium columnare growth medium (FCGM). Bacteria from four colonies at mid-exponential phase were harvested, total proteins were isolated, and identified using 2-DE MALDI TOF/TOF MS and 2-D LC ESI MS/MS analyses. The MS/MS spectra for all peptides were analyzed using sequest algorithm
Project description:Heart disease is the leading cause of death in the developed world, and its comorbidities such as hypertension, diabetes, and heart failure are accompanied by major transcriptomic changes in the heart. During cardiac dysfunction, which leads to heart failure, there are global epigenetic alterations to chromatin that occur concomitantly with morphological changes in the heart in response to acute and chronic stress. These epigenetic alterations include the reversible methylation of lysine residues on histone proteins. Lysine methylation on histone H3K4 and H3K9 were among the first methylated lysine residues identified and have been linked to gene activation and silencing, respectively. However, much less is known regarding other methylated histone residues, including histone H4K20. Trimethylation of histone H4K20 has been shown to repressive gene expression, however this mark has never been examined in the heart. Here we utilized immunoblotting and mass spectrometry to quantify histone H4K20 trimethylation in three models of cardiac dysfunction. Our results show that lysine methylation at this site is regulated in a biphasic manner leading to increased H420 trimethylation during acute hypertrophic stress and decreased H4K20 trimethylation during sustained ischemic injury and cardiac dysfunction. In addition, we examined publicly available datasets to analyze enzymes that regulate H4K20 methylation and identified one demethylase (KDM7C) and two methyltransferases (KMT5A and SMYD5) which were all upregulated in heart failure patients. This is the first study to examine histone H4K20 trimethylation in the heart and to determine how this post-translational modification is differentially regulated in multiple models of cardiac disease.
Project description:Glycoproteins isolated from elongating cotton fiber cells were analyzed using 2D-PAGE followed by MALDI TOF/TOF based protein identification. Protein isoforms were identified using Tandem mass spectrometry. Lectin based Glycopeptide enrichment strategy followed by PNGase catalyzed deglycosylation reaction was employed to assign potential N-linked glycosylation sites.
Project description:To investigate differentially accumulated proteins caused by transgenic events, comparative proteomic analysis using two-dimensional polyacrylamide gel electrophoresis was employed for Vitis vinifera ‘Thompson seedless’ leaves and transgenic Vitis vinifera ‘Thompson seedless’ leaves. Obtained proteins were digested with trypsin and subjected to MALDI-TOF-MS/MS analysis. According to annotations and a Blast search, proteins analyzed by MALDI-TOF/TOF were classified into 4 functional categories: carbon and energy metabolism, oxidation reaction, protein metabolism and resistance.
Project description:Histone deacetylases 1 and 2 (HDAC1/2) serve as the catalytic subunit of six distinct families of nuclear complexes. These complexes repress gene transcription through removing acetyl groups from lysine residues in histone tails. In addition to the deacetylase subunit, these complexes typically contain transcription factor and/or chromatin binding activities. The MIER:HDAC complex has hitherto been poorly characterized. Here we show that MIER1 unexpectedly co-purifies with an H2A:H2B histone dimer. We show that MIER1 is also able to bind a complete histone octamer. Intriguingly, we found that a larger MIER1:HDAC1:BAHD1:C1QBP complex additionally co-purifies with an intact nucleosome on which H3K27 is either di- or tri-methylated. Together this suggests that the MIER1 complex acts downstream of PRC2 to expand regions of repressed chromatin and could potentially deposit histone octamer onto nucleosome-depleted regions of DNA.