A well-connected and conserved nucleoplasmic helicase is required for production of box C/D and H/ACA snoRNAs and localization of snoRNP proteins.

Biogenesis of small nucleolar RNA-protein complexes (snoRNPs) consists of synthesis of the snoRNA and protein components, snoRNP assembly, and localization to the nucleolus. Recently, two nucleoplasmic proteins from mice were observed to bind to a model box C/D snoRNA in vitro, suggesting that they function at an early stage in snoRNP biogenesis. Both proteins have been described in other contexts.

Raised white cell count in a sick adult.

A 57 year old man presents to the emergency department in acute pulmonary oedema. Examination reveals evidence of left heart failure, 1-2 cm cervical, axillary and inguinal lymph nodes and mild splenomegaly. A full blood examination is listed in Table 1.

The farnesyl transferase inhibitor SCH 66336 induces a G(2) --> M or G(1) pause in sensitive human tumor cell lines.

SCH 66336 is a potent farnesyl transferase inhibitor (FTI) in clinical development. It efficiently prevents the membrane association of H-ras, but not K- or N-ras. Yet, in soft agar, it reverts the anchorage-independent growth of human tumor cell lines (hTCLs) harboring H-ras, K-ras, and N-ras mutations, implying that blocking farnesylation of proteins besides ras may be responsible for this effect.

Box C/D snoRNA-associated proteins: two pairs of evolutionarily ancient proteins and possible links to replication and transcription.

The eukaryotic nucleolus contains a diverse population of small nucleolar RNAs (snoRNAs) essential for ribosome biogenesis. The box C/D snoRNA family possesses conserved nucleotide boxes C and D that are multifunctional elements required for snoRNA processing, snoRNA transport to the nucleolus, and 2'-O-methylation of ribosomal RNA. We have previously demonstrated that the assembly of an snoRNP complex is essential for processing the intronic box C/D snoRNAs and that specific nuclear proteins associate with the box C/D core motif in vitro.

A binding pocket for a small molecule inhibitor of HIV-1 entry within the transmembrane helices of CCR5.

HIV-1 entry into CD4(+) cells requires the sequential interactions of the viral envelope glycoproteins with CD4 and a coreceptor such as the chemokine receptors CCR5 and CXCR4. A plausible approach to blocking this process is to use small molecule antagonists of coreceptor function. One such inhibitor has been described for CCR5: the TAK-779 molecule.

Type 2B von Willebrand's disease in thirteen individuals from five unrelated Australian families: phenotype and genotype correlations.

Type 2B von Willebrand's disease (VWD) is due to a qualitative defect in von Willebrand factor (VWF) in which there is an increased affinity for the platelet glycoprotein Ib-IX-V receptor complex. Spontaneous binding of type 2B VWF to platelets and subsequent clearance from the plasma is thought to account for the characteristic phenotype of type 2B VWD. These gain-of-function mutations are due to single amino substitutions that are clustered within the functionally important A1 domain of VWF.

Integrin alpha(v)beta(3)-mediated activation of apoptosis.

The alpha(v)beta(3) integrin mediates endothelial cell binding to the extracellular matrix and transduces an intracellular signal promoting survival of endothelial cells and various tumor cells. While the alpha(v)beta(3) integrin-mediated survival signal has been shown to be adhesion dependent, a thorough analysis has not been performed comparing the biochemical effects of antagonist binding to alpha(v)beta(3) integrin with the effects induced by the growth of cells in suspension. In this study we demonstrate that expression of alpha(v)beta(3) integrin in human embryonic kidney 293 cells transfers the alpha(v)beta(3) integrin survival pathway to an epithelial cell line.

The CC-chemokine RANTES increases the attachment of human immunodeficiency virus type 1 to target cells via glycosaminoglycans and also activates a signal transduction pathway that enhances viral infectivity.

We have studied the mechanisms by which the CC-chemokine RANTES can enhance the infectivities of human immunodeficiency virus type 1 (HIV-1) and other enveloped viruses, when present at concentrations in excess of 500 ng/ml in vitro. Understanding the underlying mechanisms might throw light on fundamental processes of viral infection, in particular for HIV-1. Our principal findings are twofold: firstly, that oligomers of RANTES can cross-link enveloped viruses, including HIV-1, to cells via glycosaminoglycans (GAGs) present on the membranes of both virions and cells; secondly, that oligomers of RANTES interact with cell-surface GAGs to transduce a herbimycin A-sensitive signal which, over a period of several hours, renders the cells more permissive to infection by several viruses, including HIV-1.

Drinking and flying: a structural model.

Background: Under a recent revision of the European Joint Aviation Authorities operations regulations it has been prohibited to act as a crew member of an aircraft with a BAC of greater than 0.02%.

Methods: This survey of UK Civil Aviation Authority pilots suggests that over 50% of respondents may have flown an aircraft with a BAC of greater than this prescribed amount.

Conserved boxes C and D are essential nucleolar localization elements of U14 and U8 snoRNAs.

Sequences necessary for nucleolar targeting were identified in Box C/D small nucleolar RNAs (snoRNAs) by fluorescence microscopy. Nucleolar preparations were examined after injecting fluorescein-labelled wild-type and mutated U14 or U8 snoRNA into Xenopus oocyte nuclei. Regions in U14 snoRNA that are complementary to 18S rRNA and necessary for rRNA processing and methylation are not required for nucleolar localization.

In vitro assembly of the mouse U14 snoRNP core complex and identification of a 65-kDa box C/D-binding protein.

The eukaryotic nucleolus contains a diverse population of small nucleolar RNAs (snoRNAs) that have been categorized into two major families based on evolutionarily conserved sequence elements. U14 snoRNA is a member of the larger, box C/D snoRNA family and possesses nucleotide box C and D consensus sequences. In previous studies, we have defined a U14 box C/D core motif that is essential for intronic U14 snoRNA processing.

Processing of vertebrate box C/D small nucleolar RNAs in plant cells.

The recent isolation of a number of plant box C/D small nucleolar (sno)RNAs demonstrates the conservation in plants of sequence and structural elements of processed box C/D snoRNAs. Boxes C and D, and terminal inverted repeats are known to be essential for accumulation and processing in vertebrates and yeast. Processing of vertebrate box C/D snoRNAs was examined by expression of various mouse hsc70 intron 5-U14 constructs in tobacco protoplasts.

Cross-reactivity to porcine factor VIII of factor VIII inhibitors in patients with haemophilia in Australia and New Zealand.

Background: Inhibitory antibodies which neutralise factor VIII develop in 10-20% of individuals with inherited haemophilia A and rarely as autoantibodies in normal individuals to cause acquired haemophilia. The antibodies are directed against human factor VIII but cross-react to varying degrees with porcine factor VIII. Porcine factor VIII can be used for treatment in individuals with low cross-reactivity.

Biochemical characterization of the binding of echistatin to integrin alphavbeta3 receptor.

Echistatin is a 49-amino-acid peptide belonging to the family of disintegrins that are derived from snake venoms and are potent inhibitors of platelet aggregation and cell adhesion. Integrin alphavbeta3 receptor plays a critical role in several physiological processes such as tumor-induced angiogenesis, tumor cell metastasis, osteoporosis and wound repair. In this study, we have characterized the binding of echistatin to purified integrin alphavbeta3 receptor and the form expressed on human embryonic kidney 293 cells.

Efficacy of p53 adenovirus-mediated gene therapy against human breast cancer xenografts.

In response to DNA damage, p53 protein accumulates in the cell nucleus causing cells to undergo DNA repair or apoptosis, programmed cell death. Reintroduction of wild-type p53 into tumors with null or mutant p53 offers a novel strategy for controlling tumor growth, by inducing apoptotic death in neoplastic cells. The efficacy of a replication-deficient p53 adenovirus construct was tested against three human breast cancer cell lines expressing mutant p53, MDA-MB-231, -468, and -435.

Identification of specific nucleotide sequences and structural elements required for intronic U14 snoRNA processing.

Vertebrate U14 snoRNAs are encoded within hsc70 pre-mRNA introns and U14 biosynthesis occurs via an intron-processing pathway. We have shown previously that essential processing signals are located in the termini of the mature U14 molecule and replacement of included boxes C or D with oligo C disrupts snoRNA synthesis. The experiments detailed here now define the specific nucleotide sequences and structures of the U14 termini that are essential for intronic snoRNA processing.

5'ETS rRNA processing facilitated by four small RNAs: U14, E3, U17, and U3.

The nucleolus, the compartment in which the large ribosomal RNA precursor (pre-rRNA) is synthesized, processed through a series of nucleolytic cleavages and modifications into the mature 18S, 5.8S, and 28S rRNAs, and assembled with proteins to form ribosomal subunits, also contains many small nucleolar RNAs (snoRNAs). We present evidence that the first processing event in mouse rRNA maturation, cleavage within the 5' external transcribed spacer, is facilitated by at least four snoRNAs: U14, U17(E1), and E3, as well as U3.

Interleukin-10 inhibits tumor metastasis through an NK cell-dependent mechanism.

Interleukin-10 (IL-10) is a recently described pleiotropic cytokine secreted mainly by type 2 helper T cells. Previous studies have shown that IL-10 suppresses cytokine expression by natural killer (NK) and type 1 T cells, thus down-regulating cell-mediated immunity and stimulating humoral responses. We here report that injected IL-10 protein is an efficient inhibitor of tumor metastasis in experimental (B16-F10) and spontaneous (M27 and Lox human melanoma) metastasis models in vivo at doses that do not have toxic effects on normal or cancer cells.

Elements essential for processing intronic U14 snoRNA are located at the termini of the mature snoRNA sequence and include conserved nucleotide boxes C and D.

Essential elements for intronic U14 processing have been analyzed by microinjecting various mutant hsc70/Ul4 pre-mRNA precursors into Xenopus oocyte nuclei. Initial truncation experiments revealed that elements sufficient for U14 processing are located within the mature snoRNA sequence itself. Subsequent deletions within the U14 coding region demonstrated that only the terminal regions of the folded U14 molecule containing con- served nucleotide boxes C and D are required for processing.

Intronic U14 snoRNAs of Xenopus laevis are located in two different parent genes and can be processed from their introns during early oogenesis.

U14 is a member of the rapidly growing family of intronic small nucleolar RNAs (snoRNAs) that are involved in pre-rRNA processing and ribosome biogenesis. These snoRNA species are encoded within introns of eukaryotic protein coding genes and are synthesized via an intron processing pathway. Characterization of Xenopus laevis U14 snoRNA genes has revealed that in addition to the anticipated location of U14 within introns of the amphibian hsc70 gene (introns 4, 5 and 7), additional intronic U14 snoRNAs are also found in the ribosomal protein S13 gene (introns 3 and 4).

The small nucleolar RNAs.

The present review summarizes key progress made in characterizing the small nucleolar RNAs (snoRNAs) of eukaryotic cells. Recent studies have shown snoRNA populations to be substantially more complex than anticipated initially. Many newly discovered snoRNAs are synthesized by an intron-processing pathway, which provides a potential mechanism for coordinating nuclear RNA synthesis.

Antitumor effect of keto-diepoxides isolated from the fungus Nattrassia mangiferae.

A novel keto-diepoxide Sch 49209 and its derivative Sch 50672, produced by the fungus Nattrassia mangiferae, inhibited tumor cell invasion through an artificial basement membrane. These compounds, at nontoxic concentrations, inhibited invasion of HT-1080 cells in a dose-dependent manner. The IC50 values for Sch 49209 and Sch 50672 were 0.

Processing of U14 small nucleolar RNA from three different introns of the mouse 70-kDa-cognate-heat-shock-protein pre-messenger RNA.

U14 is a small nucleolar RNA required for the processing of eukaryotic rRNA precursors. The U14 genes of mouse as well as rat, hamster, human, Xenopus and trout are encoded within introns of the constitutively expressed 70-kDa-cognate-heat-shock protein gene (hsc70). We demonstrate here that U14.