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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Properties of prolactin receptors were measured by monitoring [125I]prolactin binding to specific receptor sites on collagenase-dissociated mammary epithelial cells of virgin, pregnant and lactating mice. On a Scatchard plot the data generated a straight line and the estimated dissociation constant (Kd) and number of receptor sites on lactating cells were 0.9 x 10(-9) and 1540 per cell. The [125I]prolactin binding was inhibited in presence of unlabeled prolactin and other lactogenic polypeptide hormones, but not by nonlactogenic polypeptide hormones. The [125I]prolactin binding was sensitive to pronase and trypsin but not to DNAase, RNAase and hyaluronidase. Scatchard plot analysis further showed that while the number of receptors on mammary cells was variable at different stages of endocrine regulated developmental changes of the gland, Kd of the hormone--receptor complex generally remained similar. The high level of prolactin receptors on mammary cells of virgins was reduced during pregnancy and the lactating mammary cells showed a highly elevated level of prolactin receptors. The results demonstrate that specific prolactin receptors can be measured on collagenase dissociated mammary epithelial cells and this method permits a direct assessment of the number of receptors on a per cell basis rather than indirect estimates, based on average DNA or protein content of the tissue, composed of heterogeneous cell types.
Mol Cell Endocrinol 1978 Dec
PMID:Prolactin receptor on dissociated mammary epithelial cells at different stages of development. 21 95

The chromatin core particle DNA conformation deduced in broad outline by Finch et al. [Finch, J. T., Lutter, L. C., Rhodes, D., Brown, R. S., Rushton, B., Levitt, M. & Klug, A. (1977) Nature 269, 29-36] can be described in detail using other available experimental results. Histone binding sites compatible with the pattern of pancreatic DNase I digestion (Simpson, R. T. & Whitlock, J. P., Jr. (1976) Cell 9, 347-353; Noll, M. (1977) J. Mol. Biol. 116, 49-71; Lutter, L. C. (1977) J. Mol. Biol. 117, 53-69] lend to core particle DNA pseudosymmetry characteristic of molecular point group D(3). DNA symmetry and pseudosymmetry, in turn, imply equivalence and quasi-equivalence properties of the histone packing arrangement that support the following deductions: (i) One and only one alpha(2)beta(2) histone tetramer, presumably (H3)(2)(H4)(2), can serve as a stable subassembly within the histone octamer. (ii) There is a unique, strand-specific way to assign DNA binding domains to the arginine-rich histones (H3 and H4). (iii) Histones H3 and H4 alone should suffice to impose a supercoiled structure on DNA, as is observed experimentally, because only the tetramer can mimic a screw dislocation and thereby complement the screw symmetry of the DNA supercoil. (iv) The two slightly lysine-rich histones H2A and H2B are probably responsible, each in a different way, for dividing the eukaryotic chromatin fiber into discrete subunits. (v) The proposed arrangement of four distinct proteins appears to be a minimum formal requirement for making nucleosomes; that is, for introducing regularly spaced supercoiled DNA folds without also allowing formation of an indefinitely long (and genetically inert) DNA superhelix.
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PMID:Histone packing in the nucleosome core particle of chromatin. 27 80

A population of small covalently closed non-mitochondrial circular DNA molecules was isolated from the petite-negative yeast Schizosaccharomyces pombe. The mean length of these molecules, possessing the same density as nuclear DNA (1.695 g/cm3) is 1.95 +/- 0.18 micrometer. The presence of these minicircles in crude mitochondrial preparations indicates their tight association with mitochondrial particles. Their disappearance after DNase treatment of mitochondria demonstrates their extramitochondrial location.
Mol Gen Genet 1979 May 04
PMID:2 micrometer covalently closed non-mitochondrial circular DNA in the petite-negative yeast Schizosaccharomyces pombe. 28 91

Methods by which the intracellular enzymes deoxyribonuclease, ribonuclease and protease can be assayed in whole colonies of Saccharomyces cerevisiae on agar plates are described. A search for mutants deficient in deoxyribonuclease has been carried out. Two types of mutant are described. One apparently fails to produce deoxyribonuclease, ribonuclease or protease on agar plates and the other apparently fails to produce deoxyribonuclease and ribonuclease.
Mol Gen Genet 1977 Apr 29
PMID:The use of a novel plate assay in a search for yeast mutants defective in deoxyribonucleases. 32 78

Genetic recombination of phage lambda DNA mediated by Rec function of Escherichia coli was studied in the absence of duplication, transcription, translation, and maturation. Cells were jointly infected with double amber mutants, lambda D-F-I and lambda S-R-, and incubated in the presence of chloramphenicol and rifampin. The am+ recombinant DNA molecules formed within the cell were detected by in vitro packaging as viable recombinant phages. This system was used to measure the recombination activity of rec- bacteria. In recA or recA recB bacteria, the number of recombinant DNA molecules was about 1% of the rec+ level. In contrast, almost normal numbers of recombinant DNA molecules were formed in recB or recC cells. Therefore, (1) the recombination mediated by recA function does not need de novo protein synthesis; all gene products required for the recombination are present in the cell. (2) It can occur without duplication, transcription, and maturation of recombining DNA molecules. (3) The ATP dependent DNase (exonuclease V) controlled by recB and recC genes is not required for formation of recombinant DNA molecules.
Mol Gen Genet 1977 Jun 24
PMID:Formation of recombinant DNA of bacteriophage lambda by recA function of Escherichia coli without duplication, transcription, translation, and maturation. 33 Oct 71

Endonuclease alpha isolated from the nucleus of the yeast Saccharomyces cerevisiae is a DNA endonuclease which has been shown to act preferentially on denatured T7 DNA. The purified enzyme is more active with UV-irradiated native T7 DNA than with unirradiated substrate. The relation between damage, measured by pyrimidine dimer concentration, and excess endonuclease activity is most readily explained by local denaturation caused by presence of pyrimidine dimers. When three radiation sensitive mutants of yeast were tested for the level of endonuclease alpha present, none were found lacking the enzyme. However, nuclei of strain rad 1-1, a mutant that may be defective in heteroduplex repair as well as excision repair, were found to contain reduced levels of the endonuclease. The enzyme isolated from this strain had less than one half the specific activity of similar preparations from wild type yeast.
Mol Gen Genet 1978 Nov 29
PMID:Endonuclease alpha from Saccharomyces cerevisiae shows increased activity on ultraviolet irradiated native DNA. 36 83

The structure and function of the DNA--membrane complex in E. coli cells infected with bacteriophage T4 was studied. The DNA--membrane complex was isolated from the cells pulse or uniformly labeled with 3H-thymidine, fractionated by detergent treatment and separated on a discontinuous sucrose gradient. The attachment of small DNA fragments to the plasma membrane was analysed. Replicating bacteriophage T4 DNA was reversibly associated with the cytoplasmic membrane in the wall/membrane adhesion zones of the envelope. In the adhesion zone the cell wall, cytoplasmic membrane, DNA, different replicative proteins, probably form the initiation complex resistant to sonication, DNAase and Triton-X-100. This association is probably reversible. The topological aspects of bacteriophage T4 DNA replication are discussed.
Mol Biol (Mosk)
PMID:[Topological model of bacteriophage-T4 DNA replication]. 37 48

A DNA protein complex has been isolated from vegetative cells and spores of Bacillus subtilis. Properties of the DNA protein complex prepared from vegetative cells were studied and SDS gel electrophoresis was employed to compare the different DNase-untreated and -treated DNA protein complexes. It is concluded that proteins are associated with the DNA and differences in protein pattern in polyacrylamide gels indicates the involvement of DNA-binding proteins in the regulation of spore formation.
Mol Gen Genet 1978 Feb 16
PMID:Differences in pattern of a DNA protein complex isolated from vegetative cells and spores of Bacillus subtilis. 41 35

Steady state kinetics of DNA depolymerisation in the presence of the DNAase A and Mg2+ ions were investigated at pH 5.5 and wide region of the enzyme, substrate and metal ion concentrations. A model, which is consistent with experimental results obtained is suggested. According to the model catalytically active form of the DNAase A should be a metal-bound enzyme. That species reacts with the metal-free DNA to form the Michaelis complex. The kinetics observed can be described in terms of mechanism which involves covalent enzyme-substrate intermediate formation. It was shown that the second Mg2+ ion binding to the complex Mg2+ DNAase -- DNA (KD - 2.2 . 10(-3) M) enhances the kinetic parameters of the reaction. To rationalise the effect one has to assume that the rate of the intermediate formation was accelerated as a result of the second Mg2+ binding.
Mol Biol (Mosk)
PMID:[Steady state kinetics of DNA degradation with pancreatic deoxyribonuclease A in the presence of Mg2+]. 46 Jan 92

When histone is oxidized by peroxidase, its basicity (hence its complexing with DNA) is reduced: this reduction causes further alterations in the effect of histone upon the heat denaturation, acid precipitation, and breakdown by DNase of DNA, alterations which indicate that the regulation by histone of DNA expression may become abnormal. If oxidized species of histone should accumulate in the tissues in old age, the alteration mentioned might be a contributory factor of senescence.
Mol Biol Rep 1979 Dec 31
PMID:Histone: oxidation by peroxidase alters its interaction with DNA. 53 Feb 75


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