Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cosegregation of cell wall and DNA of a lysis-negative mutant of Bacillus subtilis was examined by continuously labeling (i) cell wall, (ii) DNA, and (iii) both cell wall and DNA. After four to five generations of chase in liquid media it was found by light microscope autoradiography that the numbers of wall segregation units per cell are 29 and 9 in rich and minimal medium, respectively. Under the same conditions the numbers of segregation units of DNA were almost 50% lower: 15 and 5, respectively. Simultaneous labeling of cell wall and DNA (iii) provided figures almost identical to those obtained for cell wall alone, (i), implying cosegregation of the two components. Statistical analysis ruled out their random distribution into daughter cells. Measurements of the positions of grain clusters at the end of the chase period along chains of cells, each derived from a single cell at the beginning of chase, show that cell wall units are localized according to a symmetrical pattern, whereas those of DNA are distributed in an asymmetrical but highly regular way. It appears that of two cell wall units of the same age one only has a strand of DNA attached to it. We present a simple diagrammatic model of cell wall organization and DNA-cell wall association which is compatible with our observations. Finally, we discuss previous experiments pertinent to cosegregation of cell wall and DNA obtained with cells grown on solid media as well as with germinating spores; an explanation for the independent segregation of cell wall and DNA observed in the latter case is advanced.
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PMID:Cosegregation of cell wall and DNA in Bacillus subtilis. 681 64

When Ehrlich ascites cells were cultured for 2 h under oxygen-free atmosphere, a shut-down of initiation of new replication units was observed by chain length analysis of the nascent daughter strands and by DNA fibre autoradiography. The intracellular level of ATP, ADP and AMP remained virtually normal in the anaerobized cells, while that of diadenosine 5',5'''-P1,P4-tetraphosphate was found reduced by about two orders of magnitude. It is proposed that the ceasing of DNA synthesis after O2 removal is at actively controlled regulatory response of the cells in which diadenosine 5',5"'-P1,P4-tetraphosphate is probably involved.
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PMID:Replicon initiation frequency and intracellular levels of ATP, ADP, AMP and of diadenosine 5',5'''-P1,P4-tetraphosphate in ehrlich ascites cells cultured aerobically and anaerobically. 683 47

G234 is a silent mutation located in the middle of gene b2, which controls spore pigmentation in Ascobolus immersus. Its effect on the aberrant segregation patterns of while spore mutants located in the same gene was investigated. When heterozygous, G234 decreases the frequency of aberrant segregations of the mutants located on its right, toward the low conversion end. It almost completely suppresses the aberrant 4:4 asci for mutants giving postmeiotic segregation and decreases the disparity between the 6 wild-type:2 mutant and 2 wild-type:6 mutant aberrant asci for mutants giving only these types of convertant asci. These effects are polar; G234 does not change the aberrant segregation pattern of the mutants located on its left, toward the high conversion end. This behavior suggests that G234 blocks the migration of the symmetric phase of hybrid DNA that diffuses from the high conversion end but does not prevent the formation of asymmetrical hybrid DNA. Taking into account previous observations, we conclude that the high conversion end corresponds to a region of asymmetric initiation of recombination rather than to a region of preferential ending of recombination. The asymmetric hybrid DNA first formed is further changed into a symmetric phase that extends via branch migration toward the low conversion end.
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PMID:Hybrid DNA formation during meiotic recombination. 695 Apr 8

A model is described for the templated production of frameshift and base-substitution mutations mediated through aberrant DNA structures arising as a consequence of quasi-palindromic DNA sequences. Two general mechanisms are considered. One evokes the formation and processing of imperfect DNA secondary structures (hairpins) for the production of mutations. The other evokes a "strand switch" during DNA synthesis which, in a manner unique to quasi-palindromic sequences, may be resolved to produce frameshift or base-substitution mutations, or both. It is the unique combination of symmetrical and asymmetrical elements of the quasi-palindromic sequence itself that provides the basis for both models. Through the mechanisms described, the symmetrical elements permit unusually paired DNA substrates, and the asymmetrical elements permit templated insertions, deletions, and base substitutions. The model predicts a class of mutations--simultaneously frameshifts and base substitutions--whose sequences can be predicted from a local quasi-palindromic sequence. This prediction appears to be met by a significant fraction (more than 15%) of frameshift mutations in the iso-1-cytochrome c gene of Saccharomyces cerevisiae.
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PMID:Model for the participation of quasi-palindromic DNA sequences in frameshift mutation. 705 Oct 4

DNA and protein contents of pairs of sister nuclei were determined using a combined Feulgen-dinitrofluorobenzene technique. Sister nuclei were studied in binucleate cells, induced by treatment with 0.1% caffeine, and in sister mononucleate cells of untreated roots. Excised pea roots, grown in culture, were treated with 5-aminouracil to induce mitotic synchrony and with caffeine at the time of peak mitotic index, to provide the maximum number of binucleate cells. The induced binucleate cells form a marked population which was followed through a cell cycle; sister nuclei showed a correlation of volume and protein content, r = 0.79. Protein contents of sister nuclei were rarely identical and at 1 + 2 and 1 + 6 h the difference in protein contents of sister nuclei was significant (p = 0.05). Mean nuclear protein content decreased from 1 + 2 to 1 + 6 h; then, as nuclei entered S phase, their protein content increased. From 1 + 2 to 1 + 14 h the increase in protein content, in absolute amount, was identical in both sister nuclei. This suggests that there was a biphasic pattern of protein uptake; it is differential, in sister nuclei, in the first part of G1 but is identical throughout the rest of interphase. Analysis of sister nuclei from sister mononucleate cells showed a similar pattern of change; this is further evidence, from untreated cells, of a biophasic pattern of protein uptake. Caffeine-treated nuclei had lower protein contents than untreated nuclei, yet they completed a cell cycle and entered mitosis; this suggests that nonessential proteins were no longer present. It is proposed that mitosis is asymmetrical for molecules that regulate rates of macromolecular synthesis, cell growth, and progress through a cell cycle and that once the initial asymmetry has been established, it is maintained throughout interphase, even in binucleate cells in which the two nuclei share a common cytoplasm.
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PMID:Differences in protein content of sister nuclei: evidence from binucleate and mononucleate cells. 708 48

Dinucleosomes purified from micrococcal nuclease digests of steer kidney nuclei were stripped of H1 histone by exposure to 0.50 M NaCl. They were then formed in a complex with individual subfractions of calf thymus H1 histone by dialysis of histone-dinucleosome mixtures from 0.50 M NaCl to concentrations of NaCl between 0 M and 0.08 M; between 0.30 M and 0.10 M the complexes precipitated, and so were not included in the study. The presence of H1 in the complexes was shown to cause an asymmetrical, ordered condensation as revealed by distortions of the circular dichroic spectrum of the DNA. The distortions were negligible at 0.04 M NaCl and below, and increased as a function of ionic strength between 0.05 M and 0.08 M. The degree of distortion of the spectrum, and therefore the nature of dinucleosome condensation, differed greatly from one H1 subfraction to the next. One of the three subfractions tested had almost no effect on the circular dichroism in comparing its dinucleosome complex to H1-depleted dinucleosomes. The other subfractions to different degrees produced large distortions that resulted in spectra that were of the psi type at the higher salt concentration.
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PMID:Condensation of dinucleosomes by individual subfractions of H1 histone. 727 70

The imaging appearances of a case of systemic lupus erythematosus, which manifested initially as a serositis, is described. Barium small bowel study showed segments of spiculation with tethering, angulation, and obstruction. On computed tomography there was ascites and segments of asymmetrical thickening of small bowel wall were observed. Laparotomy revealed extensive patchy serosal and peritoneal plaques but biopsy of these lesions did not lead to a definitive diagnosis. The diagnosis was made on the basis of marked elevation of antinuclear and anti-double stranded DNA antibodies.
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PMID:Systemic lupus erythematosus serositis. 748 71

The crystal structure of the self-complementary DNA octamer d(GAAGCTTC)2 complexed with N8-actinomycin D (N8AMD) has been determined at 3.0 A resolution (space group: P3(1)21; unit cell: a = 62.30, b = 62.30, c = 42.97 A; R = 0.173 for 1845 reflections). The DNA structure was severely distorted by the N8AMD bound intercalatively into the middle dinucleotide, 5'-GC-3'. The two cyclic depsipeptides, which differ from each other in overall conformation, lie in the minor groove. The complex is further stabilized by forming base--peptide and chromophore--backbone hydrogen bonds. The complexes are stacked together to form a pseudocontinuous helix running through the crystals. The structure of d(GAAGCTTC)2-actinomycin D (AMD) crystallized in the space group C2 [Kamitori S., & Takusagawa, F. (1992) J. Mol. Biol. 225, 445-456] was re-refined in order to compare it directly to the N8AMD complex structure. The asymmetrical binding mode of AMD has been confirmed on the basis of the two complex structures. The crystal structures of the N8AMD and AMD complexes bound to the same d(GAAGCTTC)2 differed by a root-mean-square deviation on all atom positions of 1.77 A, but most of the structural differences can be attributed to molecular packing in two different crystal forms, and not to structural differences induced by the interaction with the intercalating agents. However, the DNA binding and biological characteristics of N8AMD and AMD are quite different from each other. The DNA association constant of N8AMD is 33-fold less than that of AMD in an aqueous solution. N8AMD required a concentration > 10.0 microM to inhibit RNA synthesis activity in HeLa cells by 50%, whereas AMD reached to the same inhibitory level at only 35 nM. The structure of the DNA-N8AMD complex suggested that substitution of the N-methyl-L-valine residue in the cyclic depsipeptide with a N-methyl-D-valine residue might increase the hydrophobic interaction with the minor groove of the DNA. Thus the DNA association constant and RNA synthesis inhibitory activities of 5,5'-N-methyl-D-valine AMD (D-MeVal-AMD) have also been determined. The DNA association constant of D-MeVal-AMD is more than 2-fold greater than that of AMD, and the RNA synthesis inhibitory activity is about 20-fold greater.
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PMID:Structural, physical, and biological characteristics of RNA.DNA binding agent N8-actinomycin D. 754 Dec 44

1. We examined regeneration of endothelial cells (ECs), neointima formation, decreased endothelium-dependent relaxation (EDR) and changes in the contents of L-arginine, NG-monomethyl-L-arginine (L-NMMA), asymmetrical NG, NG-dimethylarginine (ADMA) and symmetrical NG,NG-dimethylarginine (SDMA) in the regenerated ECs, 6 weeks after balloon denudation of the rabbit carotid artery. 2. Regeneration of ECs was completed in 6 weeks and a significant neointima formation accompanied by the decreased EDR was observed. 3. L-NMMA and ADMA contents in the regenerated ECs (23.5 +/- 4.3 and 21.2 +/- 2.0 pmol mg-1 DNA, respectively) were significantly (P < 0.05 and P < 0.01) higher than those in the control ECs (8.8 +/- 3.0 and 7.4 +/- 1.9 pmol mg-1 DNA, respectively), whereas L-arginine was significantly (P < 0.005) decreased in the regenerated ECs (31,470 +/- 1,050 pmol mg-1 DNA) as compared to that in the control ECs (47,870 +/- 1,890 pmol mg-1 DNA). SDMA content was below the assay limits. 4. L-NMMA and ADMA, but not SDMA, inhibited the EDR induced by acetylcholine in a concentration-dependent manner. The inhibition with L-NMMA and ADMA was prevented by an addition of L-arginine, but not by D-arginine. 5. These results suggest that the accumulation of endogenous inhibitors for nitric oxide synthesis and decreased L-arginine content are associated with decreased NO production/release from regenerated ECs and neointima formation.
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PMID:Accumulation of endogenous inhibitors for nitric oxide synthesis and decreased content of L-arginine in regenerated endothelial cells. 758 95

We have discovered two unusual restriction endonuclease (ENases) in two Campylobacter jejuni strains that recognize asymmetrical, interrupted sequences and cleave the DNA both before and after their recognition sites. Both enzymes require AdoMet as a cofactor for their ENase activity.
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PMID:Two novel restriction endonucleases from Campylobacter jejuni. 760 69


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