p37mos-associated serine/threonine protein kinase activity correlates with the cellular transformation function of v-mos.

A serine/threonine-specific protein kinase activity is closely associated with v-mos-encoded proteins. Experiments were conducted with several mutant forms of p37mos to determine whether or not the kinase function correlates with the biological activity of the mutant v-mos genes. Two mutants lacking cell transformation activity, one an arginine substitution for lysine-121 in the putative ATP-binding site and the other a 23-amino acid deletion from the C-terminal end of p37mos, had no kinase activity associated with their mutant proteins. However, a third mutant with reduced biological activity had drastically less kinase activity than the wild-type protein. The latter mutant was able to phosphorylate the kinase-inactive p37mos(Arg-121) protein in vitro. These results indicate that even though p37mos(Arg-121) can be phosphorylated in trans by other kinase molecules, it lacks the ability to phosphorylate itself in vitro. This provides a compelling argument that the protein kinase function of p37mos is an intrinsic property of the protein. Moreover, since the kinase function correlates with the cellular transformation activity of the v-mos gene, we predict that it is required for the biological activity of the v-mos gene.     

Meiotic induction by Xenopus cyclin B is accelerated by coexpression with mosXe.

We have investigated the relationship between Xenopus laevis c-mos (mosXe) and the cyclin B component of maturation-promoting factor. Microinjection of Xenopus oocytes with in vitro-synthesized RNAs encoding Xenopus cyclin B1 or cyclin B2 induces the progression of meiosis, characterized by germinal vesicle breakdown (GVBD). By preinjecting oocytes with a mosXe-specific antisense oligonucleotide, we show that GVBD induced by cyclin B does not require expression of the mosXe protein. GVBD induced by cyclin B proceeds significantly faster than GVBD induced by progesterone or MosXe. However, coinjection of RNAs encoding cyclin B1 or cyclin B2 with mosXe RNA results in a 2.5- to 3-fold acceleration in GVBD relative to that induced by cyclin B alone. This acceleration of GVBD does not correlate with changes in the level of cyclin B1 and cyclin B2 phosphorylation.     

Ethidium binding to deoxyribonucleic acid: spectrophotometric analysis of analogs with amino, azido, and hydrogen substituents

The DNA–ligand interactions of a series of phenanthridinium compounds with various combinations of amino, azido, and hydrogen functions at R₃ and R₈ were examined to determine the contribution of these particular substituents to ligand binding. Spectrophometric titrations using calf-thymus DNA emphasized the importance of amino substituents in conferring a strong interaction and also stabilizing the interaction against reversal by high ionic strength. Although azido groups were not as effective as amino groups, they were more effective than hydrogen functions in enhancing the interaction. Furthermore, an amino substitution at R₈ was consistently, though only slightly, more effective than an amino substituent at R₃. The results from superhelical titrations using plasmid pBR322 DNA demonstrated that analogs with amino and/or azido functions at both R₃ and R₈ produced the greatest unwinding, and compounds with an amino or an azido function at R₈ proved more effective than those with the corresponding amino or azido substituent at R₃.     

Reduced expression of regucalcin in young and aged mdx diaphragm indicates abnormal cytosolic calcium handling in dystrophin-deficient muscle

The cytosolic Ca2+ -binding protein regucalcin is involved in intracellular signaling and present in high abundance in the liver. Here, we could show by comparative mass spectrometry-based proteomics screening of normal versus dystrophic fibres that regucalcin of 33.9 kDa and pI5.2 also exists in diaphragm muscle. Since the expression of sarcolemmal Ca2+ -leak channels and luminal Ca2+ -binding elements is altered in dystrophin-deficient muscle, we initiated this study in order to determine whether additional soluble muscle proteins involved in Ca2+ -handling are affected in muscular dystrophy. Following separation by two-dimensional gel electrophoresis, the spot pattern of the normal versus the mdx diaphragm muscle proteome was evaluated by densitometry. The expression levels of 20 major protein spots were shown to change and their identity determined by mass spectrometry. A 2-fold reduction of regucalcin in mdx diaphragm, as well as in dystrophic limb muscle and heart, was confirmed by immunoblotting in both young and aged mdx mice. The results from our proteomics analysis of dystrophic diaphragm support the concept that abnormal Ca2+ -handling is involved in x-linked muscular dystrophy. The reduction in key Ca2+ -handling proteins may result in an insufficient maintenance of Ca2+ -homeostasis and an abnormal regulation of Ca2+ -dependent enzymes resulting in disturbed intracellular signaling mechanisms in dystrophinopathies.     

Collagen-induced arthritis in common marmosets: a new nonhuman primate model for chronic arthritis

Introduction  

There is an ever-increasing need for animal models to evaluate efficacy and safety of new therapeutics in the field of rheumatoid arthritis (RA). Particularly for the early preclinical evaluation of human-specific biologicals targeting the progressive phase of the disease, there is a need for relevant animal models. In response to this requirement we set out to develop a model of collagen-induced arthritis (CIA) in a small-sized nonhuman primate species (300 to 400 g at adult age); that is, the common marmoset (Callithrix jacchus).     

CyDye immunoblotting for proteomics: co-detection of specific immunoreactive and total protein profiles

The development of ECL-Plex CyDye-conjugated secondary antibodies allows the advancement of conventional Western blotting, opening up possibilities for highly sensitive and quantitative protein confirmation and identification. We report a novel proteomic method to simultaneously visualise the total protein profile as well as the specific immunodetection of an individual protein species by combining cyanine CyDye pre-labelled proteins and antibody immunoblotting. This technique proposes to revolutionise both 2-D immunoprobing and protein confirmation following MS analysis.     

Aspects of early arthritis. What determines the evolution of early undifferentiated arthritis and rheumatoid arthritis? An update from the Norfolk Arthritis Register

Over 3500 patients with recent onset inflammatory polyarthritis (IP) have been recruited by the Norfolk Arthritis Register (NOAR) since 1990. Longitudinal data from this cohort have been used to examine the prevalence and predictors of remission, functional disability, radiological outcome, cardiovascular mortality and co-morbidity and the development of non-Hodgkin's lymphoma. Rheumatoid factor titre, high baseline C-reactive protein and high baseline HAQ score are all predictors of a poor outcome. There is a strong association between possession of the shared epitope and the development of erosions. Patients who satisfy the American College of Rheumatology criteria for rheumatoid arthritis (RA) have a worse prognosis than those who do not. However, it appears that these patients are a poorly defined subset of all those with IP rather than having an entirely separate disease entity. New statistical techniques offer exciting possibilities for using longitudinal datasets such as NOAR to explore the long-term effects of treatment in IP and RA.