Rit knockout mice and D-Ric null Drosophila were used to identify the Rit/RIC subfamily of Ras-related GTPases as regulators of an evolutionarily conserved, p38-dependent signaling cascade that functions as a survival mechanism for cells in response to reactive oxygen species exposure.

Current forms of on-line help do not adequately reflect the graphical and dynamic nature of modern graphical user interfaces. Many of today's software applications provide text-based on-line help to assist users in performing a specific task. This report describes a study in which 176 undergraduates received on-line help instructions for completing seven computer-based tasks. Instructions were provided in either written or spoken form with or without still graphic or animated visuals. Results consistently revealed that visuals, either still graphic or animated, in the on-line help instructions enabled the users to significantly perform more tasks in less time and with fewer errors than did users who did not have visuals accompanying the online help instructions. Although users receiving spoken instructions were faster and more accurate for the initial set of tasks than were users receiving written instructions, the majority of subjects preferred written instructions over spoken instructions. The results of this study suggest additional empirically-based guidelines to designers for the development of effective on-line help.

The non-peptide NK1 receptor antagonist, (±)-CP-96,345, has been evaluated for antinociceptive activity in two well-characterized inflammatory pain models in the rat. (±)-CP-96,345 abolished carrageenininduced mechanical hyperalgesia, significantly reduced carrageenin-induced paw oedema and attenuated the second phase of the formalin response. The results suggest that NK1 receptor activation occurs during the induction of inflammatory pain states in the rat.

Background: The Janus kinase (JAK) cascade is an essential and well-conserved pathway required to transduce signals for a variety of ligands in both vertebrates and invertebrates. While activation of the pathway is essential to many processes, mutations from mammals and Drosophila demonstrate that regulation is also critical. The SOCS (Suppressor Of Cytokine Signaling) proteins in mammals are regulators of the JAK pathway that participate in a negative feedback loop, as they are transcriptionally activated by JAK signaling. Examination of one Drosophila SOCS homologue, Socs36E, demonstrated that its expression is responsive to JAK pathway activity and it is capable of downregulating JAK signaling, similar to the well characterized mammalian SOCS.

Weaver is a spontaneous mutation in mice characterized by the postnatal loss of external granule cells in the cerebellum and dopaminergic neurons of the midbrain, especially in the substantia nigra. We have shown previously that natural cell death with the morphology of apoptosis occurs in the substantia nigra of normal rodents during postnatal development. We therefore sought to determine whether the loss of dopaminergic neurons in homozygous weaver mice occurs during the period of natural cell death in the substantia nigra and whether it has the morphology of apoptosis. We have found, using a silver stain technique, that although apoptotic cell death does occur early postnatally in homozygous weaver substantia nigra, it also does so with equal magnitude in wild-type and heterozygous weaver littermates. Unique to homozygous weavers is the occurrence of degenerating neurons in the nigra that are not apoptotic. These degenerating neurons are observed at postnatal day 7, and they are most abundant on postnatal days 24-25. The nonapoptotic nature of this cell death is confirmed by negative in situ end labeling of nuclear DNA fragmentation and by ultrastructural analysis. Ultrastructural studies reveal irregular chromatin aggregates in the nucleus, as well as marked cytoplasmic changes, including the formation of vacuoles and distinctive stacks of dilated cisternae of endoplasmic reticulum. We interpret these changes as indicative of either a variant morphology of programmed cell death or a pathological degenerative process mediated by an as yet unknown mechanism related to the recently described mutation in the GIRK2 potassium channel.

Prp43p catalyzes essential steps in pre-mRNA splicing and rRNA biogenesis. In splicing, Spp382p stimulates the Prp43p helicase to dissociate the postcatalytic spliceosome and, in some way, to maintain the integrity of the spliceosome assembly. Here we present a dosage interference assay to identify Spp382p-interacting factors by screening for genes that when overexpressed specifically inhibit the growth of a conditional lethal prp38-1 spliceosome assembly mutant in the spp382-1 suppressor background. Identified, among others, are genes encoding the established splicing factors Prp8p, Prp9p, Prp11p, Prp39p, and Yhc1p and two poorly characterized proteins with possible links to splicing, Sqs1p and Cwc23p. Sqs1p copurifies with Prp43p and is shown to bind Prp43p and Spp382p in the two-hybrid assay. Overexpression of Sqs1p blocks pre-mRNA splicing and inhibits Prp43p-dependent steps in rRNA processing. Increased Prp43p levels buffer Sqs1p cytotoxicity, providing strong evidence that the Prp43p DExD/H-box protein is a target of Sqs1p. Cwc23p is the only known yeast splicing factor with a DnaJ motif characteristic of Hsp40-like chaperones. We show that similar to SPP382, CWC23 activity is critical for efficient pre-mRNA splicing and intron metabolism yet, surprisingly, this activity does not require the canonical DnaJ/Hsp40 motif. These and related data establish the value of this dosage interference assay for finding genes that alter cellular splicing and define Sqs1p and Cwc23p as prospective modulators of Spp382p-stimuated Prp43p function. E IGHT phylogenetically conserved DExD/H-box proteins act at discrete steps to regulate the assembly, activation, and dissociation of the splicing apparatus (reviewed in Brow 2002; Konarska and Query 2005;Linder 2006). How these RNA-dependent ATPases are temporally and functionally regulated remains poorly understood. One putative regulator, the 83-kDa Spp382/Ntr1 protein (henceforth referred to by the Saccharomyces Genome Database standard name, Spp382p), was discovered in a screen for mutants capable of suppressing defects in yeast spliceosome assembly (Pandit et al. 2006). While spp382 null alleles are lethal, partial loss of function suppresses mutations in several other splicing factors, including the genes encoding the essential spliceosomal proteins Prp8p and Prp38p. Spp382p is a spliceosomal protein that binds the Prp43p DExD/H-box protein to promote efficient dissociation of spliceosomal factors after completion of splicing in vitro (Tsai et al. 2005). Some but not all spp382 mutants also accumulate the excised intron product of splicing in vivo, ostensibly due to protection of the intron within a hyperstabilized spliceosome (Pandit et al. 2006;Tanaka et al. 2007). The suppression of spliceosome assembly defects by spp382 mutation is proposed to occur by impairing Spp382p-stimulated dissociation of kinetically impaired or otherwise inefficient spliceosomes by Prp43p (Pandit et al. 2006). Consistent with this hypothesis, prp43 mutations also suppress spliceosome a...

Background: Integrin ␣6␤4 is overexpressed in pancreatic cancer and enhances invasion. Results: Integrin ␣6␤4 coordinately up-regulates AREG, EREG, and MMP1 through DNA demethylation and NFAT5 that in turn enhances HGF-mediated invasion. Conclusion: Integrin ␣6␤4 stimulates HGF-dependent invasion through autocrine EGFR signaling. Significance: HGF-stimulated invasion is dependent on autocrine EGFR signaling, thus implicating why EGFR inhibitors are effective in a complex tumor microenvironment.

The murine mutation weaver confers early death during development on cells in testes, cerebellum, and midbrain. The results reported here support the hypothesis that the action of weaver is intrinsic to testes and independent of Sertoli cells: germ cells are the only testicular cell type seen to die in weaver homozygotes, while Sertoli cell-dependent development of the blood testis barrier is normal. This report includes characterization of patterns of germ cell death and cerebellar granule cell death in homozygous weavers with respect to that seen during normal development by in situ end-labeling of DNA and high-magnification light microscopy. Comparison of the spatial distribution of dying cells in the weaver's cerebellum with that of dividing cells revealed disarray in the external germinal zone. The results show that cells vulnerable to weaver die by apoptotic and nonapoptotic mechanisms and indicate that weaver-induced cell death is not the consequence of extended naturally occurring developmental cell death, although their timing overlaps. Thus, although the death of cells in each region is likely to be caused by the same mutation, a base pair substitution in the G protein-coupled inwardly rectifying potassium channel 2 gene, the cell death program activated differs depending on cell type.