Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The assembly of hybrid core particles onto long chicken DNA with histone H2B in the chicken histone octamer replaced with either wheat histone H2B(2) or sea urchin sperm histone H2B(1) or H2B(2) is described. All these histone H2B variants have N-terminal extensions of between 18 and 20 amino acids, although only those from sea urchin sperm have S(T)PXX motifs present. Whereas chicken histone octamers protected 167 base pairs (bp) (representing two full turns) of DNA against micrococcal nuclease digestion (Lindsey, G. G., Orgeig, S., Thompson, P., Davies, N., and Maeder, D. L. (1991) J. Mol. Biol. 218, 805-813), all the hybrid histone octamers protected an additional 17-bp DNA against nuclease digestion. This protection was more marked in the case of hybrid octamers containing sea urchin sperm histone H2B variants and similar to that described previously (Lindsey, G. G., Orgeig, S., Thompson, P., Davies, N., and Maeder, D. L. (1991) J. Mol. Biol. 218, 805-813) for hybrid histone octamers containing wheat histone H2A variants all of which also have S(T)PXX motifs present. Continued micrococcal nuclease digestion reduced the length of DNA associated with the core particle via 172-, 162-, and 152-bp intermediates until the 146-bp core particle was obtained. These DNA lengths were approximately 5 bp or half a helical turn longer than those reported previously for stripped chicken chromatin and for core particles containing histone octamers reconstituted using "normal" length histone H2B variants. This protection pattern was also found in stripped sea urchin sperm chromatin, demonstrating that the assembly/digestion methodology reflects the in vivo situation. The interaction between the N-terminal histone H2B extension and DNA of the "linker" region was confirmed by demonstrating that stripped sea urchin sperm chromatin precipitated between 120 and 500 mM NaCl in a manner analogous to unstripped chromatin whereas stripped chicken chromatin did not. Tryptic digestion to remove all the histone tails abolished this precipitation as well as the protection of DNA outside of the 167-bp core particle against nuclease digestion.
 ...
PMID:S(T)PXX motifs promote the interaction between the extended N-terminal tails of histone H2B with "linker" DNA. 163 9

DEAE-cellulose column chromatography of Neurospora crassa soluble mycelial extracts leads to the resolution of three major protein kinase activity peaks designated PKI, PKII, and PKIII. PKII activity is stimulated by Ca2+ and Neurospora or brain calmodulin. Maximal stimulation was observed at 2 microM-free Ca2+ and 1 microgram/ml of the modulator. The stimulatory effect of the Ca(2+)-calmodulin complex was blocked by EGTA and by some calmodulin antagonists such as phenothiazine drugs or compound 48/80. PKII phosphorylates different proteins, among which histone II-A at a low concentration and CDPKS, the synthetic peptide specific for Ca(2+-)-calmodulin dependent protein kinase, are the best substrates. Some phosphorylation can be detected in the absence of any exogenous acceptor. PKII activity assayed in the presence of histone II-A or in the absence of exogenous phosphate acceptor (autophosphorylation) co-elute in a DEAE-cellulose column at 0.28 NaCl. As result of the autophosphorylation reaction of the purified enzyme a main phosphorylated component of 70 kDa was resolved by SDS-polyacrylamide gel electrophoresis. It is possible that this component is an active part of this enzyme.
Mol Cell Biochem 1991 Apr 10
PMID:Ca2+ calmodulin-dependent protein kinase activity in the ascomycetes Neurospora crassa. 165 80

Limited proteolysis of catalytic and regulatory subunits of cyclic AMP-dependent protein kinase (A-pk), cyclic AMP phosphodiesterase, glycogen synthase, and histones by fungal protease (type XIX) was analyzed by the digested peptide bands in SDS polyacrylamide gel electrophoresis. The modulatory effects on proteolysis by nucleotides, polypeptides, and phospholipids may greatly depend on the intrinsic nature of substrates. The proteolysis of the regulatory subunit of A-pk and glycogen synthase was not regulated by nucleotides and nucleic acids. In comparison, phosphatidyl serine, cardiolipin, and pepstatin A stimulated the proteolysis of the catalytic subunit of A-pk. Whereas, lambda DNA (Hind III digest), t-RNA, GTP-, phosphatidyl serine, sphingosine inhibited the proteolysis of cyclic AMP phosphodiesterase. Moreover, MS2 RNA, lambda DNA, t-RNA, dGTP, Phosphatidyl serine, phosphatidyl inositol, antipain, and chymostatin exerted inhibitory proteolytic effect on histone VIII-S. Some of these agents also had similar inhibitory effect on other types of histones (types III-S and VII-S). The inhibitory effect of phosphatidyl serine on proteolysis of histone may be due to their interaction which was monitored by the drastic increase of uv absorbance.
Mol Cell Biochem 1991 Apr 10
PMID:Regulation of fungal proteolysis on cyclic AMP-dependent protein kinase, cyclic AMP phosphodiesterase, glycogen synthase and histones. 165 82

In the studies reported here we have used topoisomerase II as a model system for analyzing the factors that determine the sites of action for DNA-binding proteins in vivo. To localize topoisomerase II sites in vivo we used an inhibitor of the purified enzyme, the antitumor drug VM-26. This drug stabilizes an intermediate in the catalytic cycle, the cleavable complex, and substantially stimulates DNA cleavage by topoisomerase II. We show that lysis of VM-26 treated tissue culture cells with sodium dodecyl sulfate induces highly specific double-strand breaks in genomic DNA, and we present evidence indicating that these double-strand breaks are generated by topoisomerase II. Using indirect end labeling to map the cleavage products, we have examined the in vivo sites of action of topoisomerase II in the 87A7 heat shock locus, the histone repeat, and a tRNA gene cluster at 90BC. Our analysis reveals that chromatin structure, not sequence specificity, is the primary determinant in topoisomerase II site selection in vivo. We suggest that chromatin organization may provide a general mechanism for generating specificity in a wide range of DNA-protein interactions in vivo.
Mol Cell Biol 1991 Oct
PMID:Chromatin structure, not DNA sequence specificity, is the primary determinant of topoisomerase II sites of action in vivo. 165 19

DNA rotational mobility in a bovine papilloma virus (BPV)-based minichromosome, autonomously replicating in mouse cells, was studied using topoisomer analysis in temperature shift experiments. It was found that in live cells the average number of topological turns increased by six in the course of temperature shift through a range of 37 degrees C. This comprised approximately 85% of the total potential mobility of naked plasmid DNA. DNA rotation in isolated nuclei was found to be 3.5-4.0 turns per 37 degrees C in 100 mM NaCl - much higher than in all experiments with animal cells reported thus far. In low salt mobility was considerably lowered. Attempts to extract minichromosomes from nuclei allowed isolation of no more than 10% of minichromosomal DNA, with could indicate a very high proportion of transcriptionally active minichromosomes in the intracellular population. Growing cells in the presence of sodium butyrate resulted not only in an increase in the level of plasmid superhelicity and a decrease of its transcription (as we report in the accompanying publication) but also reduced rotational mobility of plasmid DNA threefold (from 6 to 2 turns per 37 degrees C). The decrease in DNA rotational mobility after butyrate treatment was also partially manifested in isolated nuclei (especially at lower ionic strength). To check whether histone acetylation is directly responsible for DNA immobilization, we performed in vitro acetylation of histones using acetyl adenylate. This resulted in severe DNA immobilization in experiments using both up and down temperature shifts.
Mol Gen Genet 1991 Dec
PMID:High rotational mobility of DNA in animal cells and its modulation by histone acetylation. 166 71

We have found that histone H5 (or H1) induces physiological nucleosome spacings and extensive ordering on some plasmid constructions, but not on others, in a fully defined in vitro system. Plasmid pBR327 containing DNA insertions with lengths close to 300 base-pairs permitted histone H5 to induce a remarkable degree of nucleosome alignment. Seventeen multiples of a unit 210(+/- 4) base-pair repeat, covering the entire plasmid, were detected. Plasmid pBR327, not containing a DNA insert, permitted continuous alignment of only a few nucleosomes. These observations suggest that a necessary requirement in this system for histone H5 (or H1)-induced nucleosome alignment on small (less than 4 kb; 1 kb = 10(3) bases or base-pairs) circular plasmids may be that the total DNA length must be close to an integer multiple of the nucleosome repeat length generated, a type of boundary effect. Consistent with this hypothesis, five deletion constructs of pBR327 (not containing inserts), that spanned 64% of the plasmid, and possessed DNA lengths close to integer multiples of 210 base-pairs, permitted nucleosome alignment by histone H5. We have also found that plasmid length adjustment is not a sufficient condition for nucleosome alignment. For example, plasmids pBR322 and pUC18 did not permit nucleosome alignment when adjusted to near-integer multiples of 210 base-pairs. Also, for pBR327 that contained a length-adjusted deletion in one particular region, appreciable nucleosome alignment no longer occurred. These data suggest that a contiguous approximately 800 base-pair region of pBR327, interrupted in pBR322 and not present in pUC18, can nucleate histone H5-induced nucleosome alignment, which can then spread to adjacent chromatin. Supporting this idea, a positioned five-nucleosome array appears to originate in the required region. Additionally, on a larger (6.9 kb) plasmid construction, the "chromatin organizing region" of pBR327 and adjacent DNA on one side of it exhibited preferred H5-induced nucleosome alignment.
J Mol Biol 1991 Dec 20
PMID:Chromatin assembly on plasmid DNA in vitro. Apparent spreading of nucleosome alignment from one region of pBR327 by histone H5. 166 88

An autonomously replicating plasmid constructed from bovine papiloma virus (BPV) and pBR322 was stably maintained as a nuclear episome in a mouse cell culture. Addition to a cell culture of sodium butyrate (5 mM) induced an increase in plasmid DNA supercoiling of 3-5 turns, an increase in acetylation of cellular histones, and a decrease in plasmid transcription by 2- to 4-fold. After withdrawal of butyrate, DNA supercoiling began to fluctuate in a wave-like manner with an amplitude of up to 3 turns and a period of 3-4 h. These waves gradually faded by 24 h. The transcription of the plasmid and acetylation of cellular histones also oscillated with the same period. The wave-like alterations were not correlated with the cell cycle, for there was no resumption of DNA replication after butyrate withdrawal for at least 24 h. In vitro chemical acetylation of histones with acetyl adenylate also led to an increase in the superhelical density of plasmid DNA. The parallel changes in transcription, histone acetylation, and DNA supercoiling in vivo may indicate a functional innerconnection. Also, the observed in vivo variation in the level of DNA supercoiling directly indicates the possibility of its natural regulation in eukaryotic cells.
Mol Gen Genet 1991 Dec
PMID:Relationship of histone acetylation to DNA topology and transcription. 166 66

Ubiquitin is involved in the degradation of denatured proteins in the recovery process after various stresses. To clarify the different responses of the ubiquitin system in the hippocampal neurons after ischemia, we chose 7.5 min of sublethal forebrain ischemia in the rat. After 7.5 min of ischemia, ubiquitin-like immunoreactivity (UIR) in most of the hippocampal pyramidal cells, except for the interneurons, diminished after 3 h of reperfusion, but enhanced UIR and subsequent recovery of UIR were observed in the different hippocampal regions after 24 h of reperfusion. The most prolonged recovery of UIR in the hippocampal cells was observed in the CA1 neurons after 72 h of reperfusion. Immunoblot analysis of the proteins extracted from CA1 region showed that high-mol-wt ubiquitin conjugates (HMWUC) above 40 kDa increased, whereas free ubiquitin and ubiquitinated histone 2A decreased slightly after 4 h and 24 h of reperfusion. At 72 h of reperfusion, HMWUC decreased to the original level and free ubiquitin slightly increased beyond the control level. These results suggested that (1) diminished UIR does not always mean depletion of entire ubiquitin-protein conjugates; (2) even after sublethal ischemia, damaged proteins in the CA1 neurons may increase, and it may take a long time for elimination of these proteins.
Mol Chem Neuropathol 1991 Aug
PMID:Changes in ubiquitin and ubiquitin-protein conjugates in the CA1 neurons after transient sublethal ischemia. 166 59

Retinoic acid (RA) has been shown to be required for the maintenance of epithelial differentiation. Vitamin A deficiency in hamsters induces the tracheal epithelial cells to undergo squamous metaplasia. Reversing the vitamin deficiency restores the tracheal epithelial cells to their normal morphology and function. Using a hamster tracheal epithelial (HTE) cell culture system which undergoes differentiation to predominantly secretory cells in vitro, we found that RA can convert flat, squamous-like cells to compact, cuboidal-like cells, and that it stimulated cell proliferation. The mitogenic response to RA was maximal at 10(-7) M and required at least 48 h of treatment to observe the effect. RNA levels of growth-related genes during the growth and differentiation phases of primary HTE cultures were examined by Northern analysis. RA maintained a high level of c-myc RNA expression in preconfluent cultures, whereas untreated cells had low amounts of c-myc RNA. Expression of RNA for the replication-dependent histone 3.2 followed a similar pattern, i.e., its level was high in retinoid-treated versus control preconfluent cultures. In confluent (fully differentiated) HTE cell cultures, both retinoid-treated and control cells had low RNA levels of c-myc and histone 3.2. c-fos RNA levels were undetectable in either control or treated cells at any stage during primary culture. The RNA level of c-Ha-ras was very low in both control and treated cultures and did not vary with the state of growth or differentiation, except that when RA-treated cultures reached confluence, no c-Ha-ras RNA was detected.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Respir Cell Mol Biol 1990 Apr
PMID:The effect of retinoic acid on growth and proto-oncogene expression in hamster tracheal epithelial cells. 169 Oct 8

The antigenic domains of histone 5 (H5), a highly conserved variant of histone 1 (H1), were studied in relation to their reactivity with autoantibodies found in the sera of patients with systemic lupus erythematosus (SLE) and drug-induced lupus (DIL). While some H5 antibodies cross-react with H1, adsorption and immunoblotting studies have identified H5-specific antibodies as well. After proteolytic cleavage of H5 peptides, the reactivity of sera from these patients was tested by Western immunoblotting. All SLE (9/9) and DIL (7/7) sera bound an antigenic determinant in the carboxyl (C) terminus of H5 while none of the sera bound to the amino (N) terminus or the central hydrophobic domain. Although the reactivity of DIL sera with the purified H5 peptides was weaker than that of SLE sera, the antigenic domains bound by both groups of sera were the same. These observations demonstrate that the H5 domains reacting with DIL sera are restricted to the carboxyl terminus and are therefore no less restricted than those reacting with SLE sera. Further, the potential epitopes in the carboxyl terminus of H5 do not have a high degree of sequence identity with known mammalian peptides.
Mol Immunol 1990 Aug
PMID:Antibodies from patients with systemic lupus erythematosus and drug-induced lupus bind determinants on histone 5 (H5). 169 56


<< Previous 1 2 3 4 5 6 7 8 9 10