In previous work, we showed that highly proliferative cells and cancer cells, but not cells with normal growth rate, have tubules rich in alpha-1,2 fucosylated epitopes that extend radially from the nucleus to the cell periphery and form an unusual uptake system. The importance of alpha-1,2 fucosylation in forming tubules was demonstrated by proving that down-regulating the two corresponding fucosyltransferases (FUT1 and FUT2) causes tubule fragmentation. Here, we present evidence that in the prostate cancer cell line DU145, the tubules arise in actively growing cells from vesicles in the medial and trans elements of a partially fragmented Golgi complex, while in not actively growing cells the tubules become completely independent from the Golgi complex. Formation and elongation of the tubules proved to depend on the actin cytoskeleton, since the alpha-1,2 fucosylated protein(s) segregate with the cytoskeleton proteins, and not in the membrane fraction, as do the Golgi markers and other fucosylated proteins, while depolymerization of the actin filaments causes tubule fragmentation and shifting of the alpha-1,2 fucosylated proteins into the membrane fraction.DEAD-box (DDX) helicases are critical for recognizing viral nucleic acids to regulate antiviral innate immunity. Although DDX5 has been reported to participate in various virus infection, whether DDX5 regulates innate immune responses and its underlying mechanisms are still unknown. Here, we report that DDX5 is a negative regulator of type I IFN (IFN-I) production in antiviral responses. DDX5 knockdown significantly promoted DNA or RNA virus infection-induced IFN-I production and IFN-stimulated genes (ISGs) expression, while ectopic expression of DDX5 inhibited IFN-I production and promoted viral replication. Furthermore, we found that DDX5 specifically interacted with serine/threonine-protein phosphatase 2 A catalytic subunit beta (PP2A-Cβ) and viral infection enhanced the interaction between DDX5 and PP2A-Cβ. Besides, PP2A-Cβ interacted with IFN regulatory factor 3 (IRF3), and PP2A-Cβ knockdown promoted viral infection-induced IRF3 phosphorylation and IFN-I production. In addition, DDX5 knockdown rendered the **** more resistant to viral infection and enhanced antiviral innate immunity in vivo. Thus, DDX5 suppresses IFN-I antiviral innate immune response by interacting with PP2A-Cβ to deactivate IRF3. Together, these findings identify a negative role of DDX5 on regulating IFN-I signaling in innate immune responses.The centromere is an essential chromatin domain required for kinetochore recruitment and chromosome segregation in eukaryotes. To perform this role, centro-chromatin adopts a unique structure that provides access to kinetochore proteins and maintains stability under tension during mitosis. This is achieved by the presence of nucleosomes containing the H3 variant CENP-A, which also acts as the epigenetic mark defining the centromere. In this review, we discuss the role of CENP-A on the structure and dynamics of centromeric chromatin. We further discuss the impact of the CENP-A binding proteins CENP-C, CENP-N, and CENP-B on modulating centro-chromatin structure. Based on these findings we provide an overview of the higher order structure of the centromere.Methylation of cytosine to 5-methylcytosine (**) is a prevalent reversible epigenetic mark in vertebrates established by DNA methyltransferases (MTases); the methylation mark can be actively erased via a multi-step demethylation mechanism involving oxidation by Ten-eleven translocation (TET) enzyme family dioxygenases, excision of the latter oxidation products by thymine DNA (TDG) or Nei-like 1 (NEIL1) glycosylases followed by base excision repair to restore the unmodified state. Here we probed the activity of the mouse TET1 (mTET1) and Naegleria gruberi TET (nTET) oxygenases with DNA substrates containing extended derivatives of the 5-methylcytosine carrying linear carbon chains and adjacent unsaturated CC bonds. We found that the nTET and mTET1 enzymes were active on modified ** residues in single-stranded and double-stranded DNA in vitro, while the extent of the reactions diminished with the size of the extended group. https://www.selleckchem.com/products/srt2104-gsk2245840.html Iterative rounds of nTET hydroxylations of ssDNA proceeded with high stereo specificity and included not only the natural alpha position but also the adjoining carbon atom in the extended side chain. The regioselectivity of hydroxylation was broken when the reactive carbon was adjoined with an sp1 or sp2 system. We also found that NEIL1 but not TDG was active with bulky TET-oxidation products. These findings provide important insights into the mechanism of these biologically important enzymatic reactions.Chromatin compacts genomic DNA in eukaryotes. The primary chromatin unit is the nucleosome core particle, composed of four pairs of the core histones, H2A, H2B, H3, and H4, and 145-147 base pairs of DNA. Since replication, recombination, repair, and transcription take place in chromatin, the structure and dynamics of the nucleosome must be versatile. These nucleosome characteristics underlie the epigenetic regulation of genomic DNA. In higher eukaryotes, many histone variants have been identified as non-allelic isoforms, which confer nucleosome diversity. In this article, we review the manifold types of nucleosomes produced by histone variants, which play important roles in the epigenetic regulation of chromatin.Dermatological diagnosis remains challenging for nonspecialists because the morphologies of primary skin lesions widely vary from patient to patient. Although previous studies have used artificial intelligence (AI) to classify lesions as benign or malignant, there have not been extensive studies examining the use of AI on identifying and categorizing a primary skin lesion's morphology. In this study, we evaluate the performance of a standalone AI tool to correctly categorize a skin lesion's morphology from a test bank of images. To provide a marker of performance, we evaluate the accuracy of primary care physicians to categorize skin lesion morphology in the same test bank of images without any aids and then with the aid of a simple visual guide. The AI system achieved an accuracy of 68% in determining the single most likely morphology from the test image bank. When the AI's top prediction was broadened to its top three most likely predictions, accuracy improved to 80%. In comparison, the diagnostic accuracy of primary care physicians was 36% without any aids and 68% with the visual guide (P less then 0.
In previous work, we showed that highly proliferative cells and cancer cells, but not cells with normal growth rate, have tubules rich in alpha-1,2 fucosylated epitopes that extend radially from the nucleus to the cell periphery and form an unusual uptake system. The importance of alpha-1,2 fucosylation in forming tubules was demonstrated by proving that down-regulating the two corresponding fucosyltransferases (FUT1 and FUT2) causes tubule fragmentation. Here, we present evidence that in the prostate cancer cell line DU145, the tubules arise in actively growing cells from vesicles in the medial and trans elements of a partially fragmented Golgi complex, while in not actively growing cells the tubules become completely independent from the Golgi complex. Formation and elongation of the tubules proved to depend on the actin cytoskeleton, since the alpha-1,2 fucosylated protein(s) segregate with the cytoskeleton proteins, and not in the membrane fraction, as do the Golgi markers and other fucosylated proteins, while depolymerization of the actin filaments causes tubule fragmentation and shifting of the alpha-1,2 fucosylated proteins into the membrane fraction.DEAD-box (DDX) helicases are critical for recognizing viral nucleic acids to regulate antiviral innate immunity. Although DDX5 has been reported to participate in various virus infection, whether DDX5 regulates innate immune responses and its underlying mechanisms are still unknown. Here, we report that DDX5 is a negative regulator of type I IFN (IFN-I) production in antiviral responses. DDX5 knockdown significantly promoted DNA or RNA virus infection-induced IFN-I production and IFN-stimulated genes (ISGs) expression, while ectopic expression of DDX5 inhibited IFN-I production and promoted viral replication. Furthermore, we found that DDX5 specifically interacted with serine/threonine-protein phosphatase 2 A catalytic subunit beta (PP2A-Cβ) and viral infection enhanced the interaction between DDX5 and PP2A-Cβ. Besides, PP2A-Cβ interacted with IFN regulatory factor 3 (IRF3), and PP2A-Cβ knockdown promoted viral infection-induced IRF3 phosphorylation and IFN-I production. In addition, DDX5 knockdown rendered the mice more resistant to viral infection and enhanced antiviral innate immunity in vivo. Thus, DDX5 suppresses IFN-I antiviral innate immune response by interacting with PP2A-Cβ to deactivate IRF3. Together, these findings identify a negative role of DDX5 on regulating IFN-I signaling in innate immune responses.The centromere is an essential chromatin domain required for kinetochore recruitment and chromosome segregation in eukaryotes. To perform this role, centro-chromatin adopts a unique structure that provides access to kinetochore proteins and maintains stability under tension during mitosis. This is achieved by the presence of nucleosomes containing the H3 variant CENP-A, which also acts as the epigenetic mark defining the centromere. In this review, we discuss the role of CENP-A on the structure and dynamics of centromeric chromatin. We further discuss the impact of the CENP-A binding proteins CENP-C, CENP-N, and CENP-B on modulating centro-chromatin structure. Based on these findings we provide an overview of the higher order structure of the centromere.Methylation of cytosine to 5-methylcytosine (mC) is a prevalent reversible epigenetic mark in vertebrates established by DNA methyltransferases (MTases); the methylation mark can be actively erased via a multi-step demethylation mechanism involving oxidation by Ten-eleven translocation (TET) enzyme family dioxygenases, excision of the latter oxidation products by thymine DNA (TDG) or Nei-like 1 (NEIL1) glycosylases followed by base excision repair to restore the unmodified state. Here we probed the activity of the mouse TET1 (mTET1) and Naegleria gruberi TET (nTET) oxygenases with DNA substrates containing extended derivatives of the 5-methylcytosine carrying linear carbon chains and adjacent unsaturated CC bonds. We found that the nTET and mTET1 enzymes were active on modified mC residues in single-stranded and double-stranded DNA in vitro, while the extent of the reactions diminished with the size of the extended group. https://www.selleckchem.com/products/srt2104-gsk2245840.html Iterative rounds of nTET hydroxylations of ssDNA proceeded with high stereo specificity and included not only the natural alpha position but also the adjoining carbon atom in the extended side chain. The regioselectivity of hydroxylation was broken when the reactive carbon was adjoined with an sp1 or sp2 system. We also found that NEIL1 but not TDG was active with bulky TET-oxidation products. These findings provide important insights into the mechanism of these biologically important enzymatic reactions.Chromatin compacts genomic DNA in eukaryotes. The primary chromatin unit is the nucleosome core particle, composed of four pairs of the core histones, H2A, H2B, H3, and H4, and 145-147 base pairs of DNA. Since replication, recombination, repair, and transcription take place in chromatin, the structure and dynamics of the nucleosome must be versatile. These nucleosome characteristics underlie the epigenetic regulation of genomic DNA. In higher eukaryotes, many histone variants have been identified as non-allelic isoforms, which confer nucleosome diversity. In this article, we review the manifold types of nucleosomes produced by histone variants, which play important roles in the epigenetic regulation of chromatin.Dermatological diagnosis remains challenging for nonspecialists because the morphologies of primary skin lesions widely vary from patient to patient. Although previous studies have used artificial intelligence (AI) to classify lesions as benign or malignant, there have not been extensive studies examining the use of AI on identifying and categorizing a primary skin lesion's morphology. In this study, we evaluate the performance of a standalone AI tool to correctly categorize a skin lesion's morphology from a test bank of images. To provide a marker of performance, we evaluate the accuracy of primary care physicians to categorize skin lesion morphology in the same test bank of images without any aids and then with the aid of a simple visual guide. The AI system achieved an accuracy of 68% in determining the single most likely morphology from the test image bank. When the AI's top prediction was broadened to its top three most likely predictions, accuracy improved to 80%. In comparison, the diagnostic accuracy of primary care physicians was 36% without any aids and 68% with the visual guide (P less then 0.
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