Template-specific stimulation of RNA synthesis by phosphorylated non-histone chromatin proteins

Phosphorylated non-histone chromatin proteins are shown to stimulate the synthesis of RNA in a cell-free system using rat liver RNA polymerase and rat DNA as template. This stimulation is not observed when DNA's of other species are used as template, or when the phosphorylated proteins have been treated with alkaline phosphatase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33964/1/0000235.pd

Phosphoproteins from calf-thymus nuclei: Studies on the method of isolation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32869/1/0000247.pd

Phosphorylation of nuclear proteins in avian erythrocytes

Changes in nuclear phosphoproteins have been followed during the course of development of the avian erythrocyte. Both young reticulocytes and mature erythrocytes are capable of incorporating 32P1 into nuclear proteins, the bulk of the activity occurring in the nonhistone protein fraction. Both phosphorylation and dephosphorylation of these proteins occur at faster rates in the younger cells. As maturation proceeds, nuclear levels of both phosphoprotein kinase and protein-bound phosphorus fall several-fold. Thus changes in the metabolism and composition of these nuclear phosphoproteins correlate with changes in the structure and activity of the nucleus.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32855/1/0000231.pd

Nuclear phosphoproteins : III. Increase in phosphorylation during histone-phosphoprotein interaction

The effects of histones on the enzymatic phosphorylation of nuclear phosphoproteins have been extensively studied in vitro. Histones cause a 5- to 10-fold increase in the rate and extent of phosphorylation of nuclear phosphoprotein, with the lysine-rich histones being the most effective at stimulation. Evidence suggests that the histones are not being phosphorylated themselves, but rather act to make more sites available for phosphorylation in the phosphoprotein itself. The possible physiological significance of histone-phosphoprotein interactions is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33683/1/0000195.pd

Heterogeneity and specificity of non-histone nuclear phosphoproteins

1. 1. Extensive heterogeneity has been observed amongst the non-histone chromatin phosphoproteins from a variety of species, tissues and cell types.2. 2. Each tissue and each cell type exhibits a unique protein pattern and radioactivity profile when labeled with [32P].3. 3. The differences in nuclear phosphoproteins of liver from different species were found to increase as the species being compared diverged evolutionarily.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21851/1/0000255.pd

On the link between ocean biota emissions, aerosol, and maritime clouds: Airborne, ground, and satellite measurements off the coast of California

Surface, airborne, and satellite measurements over the eastern Pacific Ocean off the coast of California during the period between 2005 and 2007 are used to explore the relationship between ocean chlorophyll a, aerosol, and marine clouds. Periods of enhanced chlorophyll a and wind speed are coincident with increases in particulate diethylamine and methanesulfonate concentrations. The measurements indicate that amines are a source of secondary organic aerosol in the marine atmosphere. Subsaturated aerosol hygroscopic growth measurements indicate that the organic component during periods of high chlorophyll a and wind speed exhibit considerable water uptake ability. Increased average cloud condensation nucleus (CCN) activity during periods of increased chlorophyll a levels likely results from both size distribution and aerosol composition changes. The available data over the period of measurements indicate that the cloud microphysical response, as represented by either cloud droplet number concentration or cloud droplet effective radius, is likely influenced by a combination of atmospheric dynamics and aerosol perturbations during periods of high chlorophyll a concentrations

Stimulation of uterine nonhistone protein phosphorylation and nuclear protein kinase activity by estradiol-17[beta]

Changes in the phosphorylation of nonhistone chromosomal proteins have been followed in rat uterus stimulated by 17[beta]-estradiol. Isolated uteri were found to incorporate 32Pi into nonhistone proteins via an endogenous nuclear protein kinase reaction. The rate of 32P labeling of nonhistone proteins and the activity of nuclear protein kinase(s) were found to be elevated over three- and two-fold respectively in uteri obtained from ovariectomized animals treated with estrogen. A dramatic change was observed in the radioactivity profile of 32P-labeled proteins fractionated via sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These observations are compatable with the hypothesis that phosphorylation of nonhistone proteins plays a role in the regulation of gene activity in the uterus.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21747/1/0000141.pd

Partial purification and properties of a chromatin-associated phosphoprotein kinase from rat liver nuclei

A phosphoprotein kinase (EC 2.7.1.37) KIVb, from rat liver nuclei, was purified 75-fold by phosphocellulose chromatography and gel filtration on Sephadex G-200. The enzyme, which has an apparent molecular weight of 55 000, phosphorylates casein and chromatin-bound nonhistone proteins more readily than histones or ribosomal proteins. It exhibits an absolute requirement for divalent cation with optimum activity at 15-20 mM Mg2+. Maximal kinase activity is achieved at 100 mM NaCl. The pH vs. activity curve is biphasic with optima at pH 6.5 and pH 8.0. The Km value for casein is 280 [mu]g/ml and the Km for ATP is 6 [middle dot] 10-6 M.Kinase KIVb phosphorylates numerous nonhistone nuclear proteins as shown by electrophoretic analysis. The addition of kinase KIVb to reaction mixtures containing nonhistone proteins results in the phosphorylation of a spectrum of polypeptides similar to those that are phosphorylated by endogenous nuclear kinases. Nonhistone proteins bound to chromatin appear to be better substrates for KIVb than nonhistones dissociated from chromatin. A comparison of nuclear phosphoproteins phosphorylated either in the intact animal or in vitro (by the addition of kinase KIVb) indicates some differences and some similarities in the patterns of phosphorylation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21840/1/0000243.pd

Increased RNA synthesis in nuclei isolated from rat liver tissue slices incubated with cyclic adenosine 3',5'-monophosphate or glucagon

Incubation of rat liver tissue slices with cyclic adenosine 3',5'-monophosphate (cyclic AMP) for 30 min results in a dose-dependent increase in RNA synthesizing capacity of nuclei prepared from these slices, with a doubling of synthetic rate observed at 10-7 cyclic AMP. The cyclic AMP effect is observed when RNA polymerase activity is measured either in the presence of Mg2+ and low ionic strength, or Mn2+ and high ionic strength. Experiments employing saturating amounts of exogenous bacterial RNA polymerase suggest that the cyclic AMP-induced stimulation occurs primarily at the level of template activity. Other cyclic nucleotides tested in the same manner are ineffective in stimulating RNA synthesis by tissue slice nuclei. In addition to cyclic AMP, adenosine 5'-monophosphate (5'-AMP) consistently produced small increases in nuclear RNA synthesis although never of the magnitude seen with the cyclic nucleotide.An increased capacity for RNA synthesis is also seen in nuclei isolated from liver slices incubated with glucagon at concentrations from 0.5 [mu]g/ml to 50 [mu]g/ml. A maximal stimulation of approximately twofold occurs at a glucagon concentration of 1.0 [mu]g/ml. Liver slices incubated with optimal concentrations of cyclic AMP and glucagon simultaneously show that the effects of the two agents on RNA synthesis are not additive.The results indicate that cyclic AMP at physiological concentrations can stimulate RNA synthetic capacity in vitro, and that the effect mimics a similar response to glucagon. Since it is known that glucagon causes an increase in liver concentrations of cyclic AMP and a subsequent induction of some liver enzymes, it is suggested that cyclic AMP-mediated control of RNA synthesis may be involved in such regulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33774/1/0000026.pd

n-Alkanes, PAHs and surfactants in the sea surface microlayer and sea water samples of the Gerlache Inlet sea (Antarctica)

Sea surface microlayer (SML) and sea water samples (SSW) collected in the Gerlache Inlet Sea (Antarctica) were analysed for n-alkanes and polycyclic aromatic hydrocarbons (PAHs). The SML is a potential enrichment site of hydrophobic organic compounds compared to the underlying water column. Total concentration ranges of n-alkanes and PAHs (dissolved and particulate) in subsurface water (−0.5 m depth) were 272– 553 ng l−1 (mean: 448 ng l−1) and 5.27–9.43 ng l−1 (mean: 7.06 ng l−1), respectively. In the SML, the concentration ranges of n-alkanes and PAHs were 353–968 ng l−1 (mean: 611 ng l−1) and 7.32–23.94 ng l−1 (mean: 13.22 ng l−1), respectively. To evaluate possible PAH contamination sources, specific PAH ratios were calculated. The ratios reflected a predominant petrogenic input. A characterisation of surface active substances was also performed on SML and SSW samples, both by gas bubble extraction, and by dynamic surface tension measurements. Results showed a good correlation between n-alkanes, PAHs and refractory organic matter