NK cells prevent T cell lymphoma development in T cell receptor-transgenic mice.

Mice that express a single transgenic T cell receptor have a low incidence of T cell lymphoma development. We investigated whether this tumor development is restricted by surveillance mechanisms that are exerted by IL-15-dependent cells. Lymphoma incidence was increased to between 30 and 60% when TCR transgenes were expressed in IL-15-deficient mice.

Let-7 microRNAs target the lineage-specific transcription factor PLZF to regulate terminal NKT cell differentiation and effector function.

Lethal-7 (let-7) microRNAs (miRNAs) are the most abundant miRNAs in the genome, but their role in developing thymocytes is unclear. We found that let-7 miRNAs targeted Zbtb16 mRNA, which encodes the lineage-specific transcription factor PLZF, to post-transcriptionally regulate PLZF expression and thereby the effector functions of natural killer T cells (NKT cells). Dynamic upregulation of let-7 miRNAs during the development of NKT thymocytes downregulated PLZF expression and directed their terminal differentiation into interferon-γ (IFN-γ)-producing NKT1 cells.

B cell super-enhancers and regulatory clusters recruit AID tumorigenic activity.

The antibody gene mutator activation-induced cytidine deaminase (AID) promiscuously damages oncogenes, leading to chromosomal translocations and tumorigenesis. Why nonimmunoglobulin loci are susceptible to AID activity is unknown. Here, we study AID-mediated lesions in the context of nuclear architecture and the B cell regulome.

Genome-wide association study of prostate cancer identifies a second risk locus at 8q24.

Recently, common variants on human chromosome 8q24 were found to be associated with prostate cancer risk. While conducting a genome-wide association study in the Cancer Genetic Markers of Susceptibility project with 550,000 SNPs in a nested case-control study (1,172 cases and 1,157 controls of European origin), we identified a new association at 8q24 with an independent effect on prostate cancer susceptibility. The most significant signal is 70 kb centromeric to the previously reported SNP, rs1447295, but shows little evidence of linkage disequilibrium with it.

Co-operative functions between nuclear factors NFkappaB and CCAT/enhancer-binding protein-beta (C/EBP-beta) regulate the IL-6 promoter in autocrine human prostate cancer cells.

Background: IL-6 is a growth and survival factor for prostate cancer cells through autocrine pathways. Here, we have systematically examined the transcriptional regulation mechanisms of IL-6 in autocrine prostate cancer cells.

Methods: RT-PCR and immunohistochemical staining were used to determine IL-6 production in the cells.

Epigenetic Up-regulation of Gene Expression in KAS 6/1 Human Multiple Myeloma Cells.

Cytosine methylation, an epigenetic form of regulating gene transcription, has gained importance upon the discovery that genes involved in the carcinogenic process may be regulated by this mechanism and, moreover, that certain cancers respond to treatment with demethylation-promoting drugs. Typically, the use of DNA methyltransferase inhibitor drugs results in the up-regulation of important tumor suppressor genes, previously down-regulated by the existence of abnormal cytosine methylation within their promoters. Here, we show microarray and RT-PCR results indicating that many genes are down-regulated upon treatment of KAS 6/1 multiple myeloma cells with Zebularine, a demethylating agent.

Structure of monellin refined to 2.3 a resolution in the orthorhombic crystal form.

The structure of orthorhombic crystals of monellin, a sweet protein extracted from African serendipity berries, has been solved by molecular replacement and refined to 2.3 A resolution. The final R factor was 0.

Transcription termination: primary intermediates and secondary adducts.

In living organisms, stable elongation complexes of RNA polymerase dissociate at specific template positions in a process of transcription termination. It has been suggested that the dissociation is not the immediate cause of termination but is preceded by catalytic inactivation of the elongation complex. In vitro reducing ionic strength can be used to stabilize very unstable and catalytically inactive complex at the point of termination; the previous biochemical characterization of this complex has led to important conclusions regarding termination mechanism.

Interleukin-6 regulation of the human DNA methyltransferase (HDNMT) gene in human erythroleukemia cells.

Methylation of mammalian DNA by the DNA methyltransferase enzyme (dnmt-1) at CpG dinucleotide sequences has been recognized as an important epigenetic control mechanism in regulating the expression of cellular genes (Yen, R. W., Vertino, P.

Enhancement of N-nitrosodiethylamine-initiated hepatocarcinogenesis by phentoin in male F344/NCr rats at a dose causing maximal induction of CYP2B.

The effect of the clinically important anticonvulsant phenytoin (DPH) on hepatocarcinogenesis of male F344/NCr rats initiated with a single i.p. dose of N-nitrosodiethylamine (75 mg/kg b.

A novel interaction of tRNA(Lys,3) with the feline immunodeficiency virus RNA genome governs initiation of minus strand DNA synthesis.

Complementarity between nucleotides at the 5' terminus of tRNA(Lys,3) and the U5-IR loop of the feline immunodeficiency virus RNA genome suggests a novel intermolecular interaction controls initiation of minus strand synthesis in a manner analogous to other retroviral systems. Base pairing of this tRNA-viral RNA duplex was confirmed by nuclease mapping of the RNA genome containing full-length or 5'-deleted variants of tRNA(Lys,3) hybridized to the primer-binding site. A major pause in RNA-dependent DNA synthesis occurred 14 nucleotides ahead of the primer-binding site with natural and synthetic tRNA(Lys,3) primers, indicating it was not a consequence of tRNA base modifications.

alpha 1-Antichymotrypsin is the human plasma inhibitor of macrophage ectoenzymes that cleave pro-macrophage stimulating protein.

Macrophage stimulating protein (MSP) is secreted as 78-kDa single chain pro-MSP, which is converted to biologically active, disulfide-linked alphabeta chain MSP by cleavage at Arg(483)-Val(484). Murine resident peritoneal macrophages have two cell surface proteolytic activities that cleave pro-MSP. One is a pro-MSP convertase, which cleaves pro-MSP to active MSP; the other degrades pro-MSP.

Structures of furanosides: geometrical analysis of low-temperature X-ray and neutron crystal structures of five crystalline methyl pentofuranosides.

Crystal structures of all five crystalline methyl D-pentofuranosides, methyl alpha-D-arabinofuranoside (1), methyl beta-D-arabinofuranoside (2), methyl alpha-D-lyxofuranoside (3), methyl beta-D-ribofuranoside (4) and methyl alpha-D-xylofuranoside (5) have been determined by means of cryogenic X-ray and neutron crystallography. The neutron diffraction experiments provide accurate, unbiased H-atom positions which are especially important because of the critical role of hydrogen bonding in these systems. This paper summarizes the geometrical and conformational parameters of the structures of all five crystalline methyl pentofuranosides, several of them reported here for the first time.

Correlation of human CD56+ cell cytotoxicity and IFN-gamma production.

The use of an IFN-gamma ELISPOT assay to evaluate cellular immune responses has gained increasing popularity, especially as a surrogate measure for cytotoxic T lymphocyte (CTL) responses. We have compared the IFN-gamma ELISPOT assay and the traditional(51)Cr release assay for detection of human natural killer (NK) cell activity. The cell populations used for evaluation of these assays included freshly isolated and IL-2-activated peripheral blood mononuclear cells (PBMC).

Leukemia inhibitory factor can substitute for nidatory estrogen and is essential to inducing a receptive uterus for implantation but is not essential for subsequent embryogenesis.

A stage critical in mammalian development is embryo implantation. At this point, the blastocyst establishes a close interaction with the uterine tissues, a step necessary for its continued embryonic development. In many mammalian species, including man, uterine expression of the cytokine, leukemia inhibitory factor (LIF) is coincident with the onset of implantation and in mice LIF is essential to this process.

A case for sliding SeqA tracts at anchored replication forks during Escherichia coli chromosome replication and segregation.

SeqA is an Escherichia coli DNA-binding protein that acts at replication origins and controls DNA replication. However, binding is not exclusive to origins. Many fragments containing two or more hemi-methylated GATC sequences bind efficiently.

Quantitative reactions of anti 5,9-dimethylchrysene dihydrodiol epoxide with DNA and deoxyribonucleotides.

Native as well as denatured calf thymus DNA, deoxyguanylic and deoxyadenylic acid, respectively, were reacted with the racemic anti 5,9-dimethylchrysene dihydrodiol epoxide (5,9-DMCDE). The deoxyribonucleoside adducts were separated by HPLC and characterized by CD and NMR. Approximately 17% of the epoxide was trapped by native DNA and 76% of the adducts were derived from the RSSR enantiomer.

swi1 and swi3 perform imprinting, pausing, and termination of DNA replication in S. pombe.

The developmental program of cell-type switching of S. pombe requires a strand-specific imprinting event at the mating-type locus (mat1). Imprinting occurs only when mat1 is replicated in a specific direction and requires several trans-acting factors.

Mapping the binding site of colchicinoids on beta -tubulin. 2-Chloroacetyl-2-demethylthiocolchicine covalently reacts predominantly with cysteine 239 and secondarily with cysteine 354.

2-Chloroacetyl-2-demethylthiocolchicine (2CTC) and 3-chloroacetyl-3-demethylthiocolchicine (3CTC) resemble colchicine in binding to tubulin and react covalently with beta-tubulin, forming adducts with cysteine residues 239 and 354. The adducts at Cys-239 are less stable than those at Cys-354 during formic acid digestion. Extrapolating to zero time, the Cys-239 to Cys-354 adduct ratio is 77:23 for 2CTC and 27:73 for 3CTC.

Human immunodeficiency virus type 1 nucleocapsid protein can prevent self-priming of minus-strand strong stop DNA by promoting the annealing of short oligonucleotides to hairpin sequences.

Understanding how viral components collaborate to convert the human immunodeficiency virus type 1 genome from single-stranded RNA into double-stranded DNA is critical to the understanding of viral replication. Not only must the correct reactions be carried out, but unwanted side reactions must be avoided. After minus-strand strong stop DNA (-sssDNA) synthesis, degradation of the RNA template by the RNase H domain of reverse transcriptase (RT) produces single-stranded DNA that has the potential to self-prime at the imperfectly base-paired TAR hairpin, making continued DNA synthesis impossible.

The structure of human beta-defensin-2 shows evidence of higher order oligomerization.

Defensins are small cationic peptides that are crucial components of innate immunity, serving as both antimicrobial agents and chemoattractant molecules. The specific mechanism of antimicrobial activity involves permeabilization of bacterial membranes. It has been postulated that individual monomers oligomerize to form a pore through anionic membranes, although the evidence is only indirect.

Solid-state UV laser-induced fluorescence detection in capillary electrophoresis.

Two solid-state UV lasers were applied to the laser-induced fluorescence (LIF) detection of various groups of compounds after separation by capillary electrophoresis. These lasers are thermoelectric-cooled, highly compact, and inexpensive. Such lasers provide few mW of quasi-continuous wave (CW) power which are sufficient and stable for LIF detection.

The role of steric hindrance in 3TC resistance of human immunodeficiency virus type-1 reverse transcriptase.

Treating HIV infections with drugs that block viral replication selects for drug-resistant strains of the virus. Particular inhibitors select characteristic resistance mutations. In the case of the nucleoside analogs 3TC and FTC, resistant viruses are selected with mutations at amino acid residue 184 of reverse transcriptase (RT).

Tumorigenesis mediated by MET mutant M1268T is inhibited by dominant-negative Src.

We recently described germline and somatic mutations in the MET gene associated with papillary renal carcinoma type 1. MET mutation M1268T was located in a codon highly conserved among receptor tyrosine kinases, and homologous to the codon mutated in multiple endocrine neoplasia type 2B, and many cases of sporadic medullary carcinoma of the thyroid gland (Ret M918T). Ret M918T and MET M1268T have previously been shown to be highly active in mouse NIH3T3 transformation assays, and to change the substrate specificity of the kinase.