Human herpesvirus 7 open reading frame U12 encodes a functional beta-chemokine receptor

Human herpesvirus 7 (HHV-7), which belongs to the betaherpesvirus subfamily, infects mainly CD4+ T cells in vitro and infects children during infancy. After the primary infection, HHV-7 becomes latent. HHV-7 contains two genes (U12 and U51) that encode putative homologs of cellular G-protein-coupled receptors. To analyze the biological function of the U12 gene, we cloned the gene and expressed the U12 protein in cells. The U12 gene encoded a calcium-mobilizing receptor for the EBI1 ligand chemokine-macrophage inflammatory protein 3beta (ELC/MIP-3beta) but not for other chemokines, suggesting that the chemokine selectivity of the U12 gene product is distinct from that of the known mammalian chemokine receptors. These studies revealed that U12 activates distinct transmembrane signaling pathways that may mediate biological functions by binding with a beta-chemokine, ELC/MIP-3beta.     

Poly(ADP-ribose) polymerase 1 binds to Kaposi's sarcoma-associated herpesvirus (KSHV) terminal repeat sequence and modulates KSHV replication in latency

During latency, Kaposi's sarcoma-associated herpesvirus (KSHV) is thought to replicate once and to be partitioned in synchrony with the cell cycle of the host. In this replication cycle, the KSHV terminal repeat (TR) sequence functions as a replication origin, assisted by the latency-associated nuclear antigen (LANA). Thus, TR seems to function as a cis element for the replication and partitioning of the KSHV genome. Viral replication and partitioning are also likely to require cellular factors that interact with TR in either a LANA-dependent or -independent manner. Here, we sought to identify factors that associate with TR by using a TR DNA column and found that poly(ADP-ribose) polymerase 1 (PARP1) and known replication factors, including ORC2, CDC6, and Mcm7, bound to TR. PARP1 bound directly to a specific region within TR independent of LANA, and LANA was poly(ADP-ribosyl)ated by PARP1. Drugs such as hydroxyurea and niacinamide, which raise or lower PARP activity, respectively, affected the virus copy number in infected cells. Thus, the poly(ADP-ribosyl)ation status of LANA appears to affect the replication and/or maintenance of the viral genome. Drugs that specifically up-regulate PARP activity may lead to the disappearance of latent KSHV.     

Extraction of correlated gene clusters from multiple genomic data by generalized kernel canonical correlation analysis

MOTIVATION: A major issue in computational biology is the reconstruction of pathways from several genomic datasets, such as expression data, protein interaction data and phylogenetic profiles. As a first step toward this goal, it is important to investigate the amount of correlation which exists between these data. RESULTS: These methods are successfully tested on their ability to recognize operons in the Escherichia coli genome, from the comparison of three datasets corresponding to functional relationships between genes in metabolic pathways, geometrical relationships along the chromosome, and co-expression relationships as observed by gene expression data.     

Elevation of cytoplasmic free calcium concentration by stable thromboxane A2 analogue in human platelets

9, 11-Epithio-11, 12-methano-thromboxane A2 (STA2), a stable analogue of thromboxane A2, caused a rapid rise in cytoplasmic free Ca2+ concentration ([Ca2+]i) in human platelets as measured with the fluorescent Ca2+ indicator quin2. Concomitantly, this compound induced phosphorylation of myosin light chain which is catalyzed by Ca2+, calmodulin-dependent protein kinase. These reactions were fast enough to trigger serotonin release. 13-Azaprostanoic acid, a receptor level antagonist of thromboxane A2 inhibited STA2-induced elevation of [Ca2+]i, phosphorylation of myosin light chain and serotonin release. These results provide evidence that STA2 interacts with a thromboxane A2 receptor which leads to elevation of [Ca2+]i.     

Temperature-sensitive mutants of human cytomegalovirus.

Eight temperature-sensitive mutants of human cytomegalovirus have been isolated after mutagenesis with nitrosoguanidine. Three of these mutants have been classified into three separate complementation groups and are capable of synthesizing virus DNA at the nonpermissive temperature (39.5 degrees C). Two others appear unable to synthesize virus DNA at the elevated temperature.     

Studies on human finger tapping neural networks by phase transition curves

Generally, the phase resetting experiments can be used to investigate the behaviors of the stable biological oscillators (e.g. circadian rhythms, biochemical oscillators, pacemaker neurons, bursting neurons). Winfree found that there are two types of phase transition curves (PTC) in the phase resetting experiments of biochemical oscillations. The one is the curve with an average slope of unity (Type 1) and is obtained for the small magnitude of perturbation. The other curve is that with a zero average slope (Type 0) and is obtained for the large magnitude of perturbation. Previously, we explained these results mathematically by the homotopy theory. In this paper, some properties of the human finger tapping neural network are studied psychologically using PTC on the basis of above theoretical results: assuming that an oscillatory neural network controls the human finger tapping, we performed two kinds of phase resetting experiments on the finger tapping. In the first experiment, we showed that the PTC was available to estimate the degree of functional interaction between the finger tapping neural network and that which controls another task. Three tasks (rapid key-pushing, rapid voicing and pattern discrimination) were chosen as the perturbation of the phase resetting experiment. Analyzing shapes of PTCs, it was found that the interaction with the key-pushing network was the largest, and that with the pattern recognition network was the smallest of the three. In the second experiment, we modified the first task as perturbation of the phase resetting experiments to investigate further the interactions between the left and the right hand motor systems. Consequently the following results were revealed. First, shapes of PTCs are very different according as subject's experiences of finger tapping. Second, the type of PTC for some subjects changes from Type 0 to Type 1 by learning. Third, the PTC tends to become Type 0 for shorter tapping periods. Fourth, neither changes of motor loads (the necessary force to push the key) nor an alternation of the tapping hand and the key-pushing hand affects the shape of PTCs.     

The removal of non-collagen components from newborn calf dermis with magnesium chloride solution.

1. Non-collagenous substances in newborn calf dermis were extracted with solutions of various concentrations of MgCl2. The total protein and hydroxyproline contents in MgCl2 extracts increased with increase in the concentration of MgCl2 in the solutions. In particular, steep increases of their contents were observed at concentrations of MgCl2 from 0.5 to 1.0 M. Total amounts of hydroxyproline in 1.0, 2.0, and 3.0 M MgCl2 extracts were equivalent to 40-50% of the hydroxyproline content in the whole connective tissue. Hexose and hexosamine contents of MgCl2 extracts increased with increase of the MgCl2 concentration. Hexuronic acid was hardly present in the residues after extractions with 0.5, 1.0, 2.0, and 3.0 M MgCl2. 2. Plasma proteins, hyaluronic acid, and dermatan sulfate were extracted at low concentrations of MgCl2. A non-collagenous protein and MgCl2-soluble collagen were extracted with 1.0, 2.0, and 3.0 M MgCl2 solutions. The disperson of collagen fibrils was observed in the residue extracted with 1.0 M MgCl2 solution by electron microscopy; the fibril structure of collagen was disordered by extraction with 2.0 and 3.0 M MgCl2. The results suggest that the dispersion and disorder of collagen fibrils lead to the release of a non-collagenous protein. Furthermore, it is suggested that the removal of hyaluronic acid and dermatan sulfate was not very effective for the solubilization of a large amount of collagen, but was suitable as a pretreatment to the extraction of a non-collagenous protein accompanied by the solubilization of a large amount of collagen. 3. The non-collagenous protein was purified by DEAE-cellulose column chromatography. Polyacrylamide gel electrophoresis of this protein at pH 8.5 showed a single band moving to the cathode. The non-collagenous protein contained 3.7% hexose, 1.8% hexosamine, and no hexuronic acid. This protein is rich in glycine, glutamic acid, and alanine, and contains neither hydroxyproline nor hydroxylysine. Sedimentation analysis showed a single peak with 1.8 S and the molecular weight was approx. 43,000 as determided by SDS polyacrylamide gel electrophoresis.     

Comparison of the Complete DNA Sequences of Human Herpesvirus 6 Variants A and B

Human herpesvirus 6 (HHV-6), which belongs to the betaherpesvirus subfamily and infects mainly T cells in vitro, causes acute and latent infections. Two variants of HHV-6 have been distinguished on the basis of differences in several properties. We have determined the complete DNA sequence of HHV-6 variant B (HHV-6B) strain HST, the causative agent of exanthem subitum, and compared the sequence with that of variant A strain U1102. A total of 115 potential open reading frames (ORFs) were identified within the 161,573-bp contiguous sequence of the entire HHV-6 genome, including some genes with remarkable differences in amino acid identity. All genes with <70% identity between the two variants were found to contain deleted regions when ORFs that could not be expressed were excluded from the comparison. Except in the case of U47, these differences were found in immediate-early/regulatory genes, DR2, DR7, U86/90, U89/90, and U95, which may represent characteristic differences of variants A and B. Also, we have successfully typed 14 different strains belonging to variant A or B by PCR using variant-specific primers; the results suggest that the remarkable differences observed were conserved evolutionarily as variant-specific divergence.