scholarly journals Lack of nucleosomal structure in a DNase-I-solubilized transcriptionally active chromatin fraction of Physarum polycephalum

2008 ◽  
Vol 147 (3) ◽  
pp. 575-580 ◽  
Author(s):  
Marta CZUPRYN ◽  
Kazimierz TOCZKO
Keyword(s):  
Physarum Polycephalum ◽  
Dnase I ◽  
Active Chromatin ◽  
Chromatin Fraction ◽  
Nucleosomal Structure

An active chromatin structure acquired by translocated c-myc genes

1986 ◽  
Vol 6 (4) ◽  
pp. 1357-1361
Author(s):  
E Kakkis ◽  
J Prehn ◽  
K Calame
Keyword(s):  
Chromatin Structure ◽  
Gene Segment ◽  
Dnase I ◽  
Regulatory Sequences ◽  
Active Chromatin ◽  
Alpha Gene

We used general sensitivity to DNase I digestion to analyze the chromatin structure of c-myc genes in seven murine plasmacytomas. In every case, the 3' portion of c-myc juxtaposed with C alpha displayed a much more DNase I-sensitive chromatin structure than untranslocated c-myc or, in one case analyzed, the reciprocally translocated 5' portion. Our data suggest the presence of regulatory sequences near the C alpha gene segment.

scholarly journals Histone composition of a chromatin fraction containing ribosomal deoxyribonucleic acid isolated from the macronucleus of Tetrahymena pyriformis

1978 ◽  
Vol 173 (1) ◽  
pp. 155-164 ◽  
Author(s):  
R W Jones
Keyword(s):  
Ribosomal Dna ◽  
Sodium Dodecyl Sulphate ◽  
Gel Electrophoresis ◽  
Deoxyribonucleic Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Tetrahymena Pyriformis ◽  
Active Chromatin ◽  
Chromatin Fraction ◽  
Inactive Chromatin

The histone compositions of a chromatin fraction containing ribosomal DNA and of the remaining macronuclear chromatin of Tetrahymena pyriformis was analysed by gel electrophoresis. These chromatin fractions were used as models for transcriptionally active and inactive chromatin respectively. The extent of histone modification, as indicated by the distribution of histone between differently charged subspecies in acid-urea gels, is not grossly different in the two chromatin fractions. However, histone H1 is present, but may be differently modified in the two chromatin fractions. The histone/DNA ratio in ribosomal chromatin, measured after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of samples of chromatin, was found to be the same whether chromatin was extracted from growing or stationary organisms, and to be approx. 40% of this ratio in the remaining macronuclear chromatin. The implications of these results for the possible structure of transcriptionally active chromatin are discussed.

scholarly journals Structure of active chromatin: isolation and characterization of transcriptionally active chromatin from rat liver

1997 ◽  
Vol 322 (1) ◽  
pp. 273-279 ◽  
Author(s):  
Kulbhushan TIKOO ◽  
Sunita GUPTA ◽  
Q. Anwar HAMID ◽  
Vanya SHAH ◽  
Bishwanath CHATTERJEE ◽  
...  
Keyword(s):  
Rat Liver ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
Micrococcal Nuclease ◽  
Active Chromatin ◽  
Chromatin Fraction ◽  
Isolation And Characterization ◽  
Bivalent Cations ◽  
Composite Gel ◽  
A Minor

Rat liver nuclei were isolated in low-ionic-strength buffer in the absence of bi- and multi-valent cations. Digestion of these nuclei by endogenous nuclease, micrococcal nuclease and DNase I revealed that a minor chromatin fraction was preferentially digested into poly- and oligo-nucleosomes. Southern blot hybridization with various active gene probes confirmed that these chromatin fragments represent coding and 5ƀ upstream regions of transcriptionally active chromatin. Active chromatin fragments were released selectively into the medium, with inactive chromatin remaining inside the nuclei, under the above ionic conditions. The inclusion of bivalent cations during the digestion of nuclei reversed the solubility behaviour of active chromatin. Rearrangement and exchange of histone H1 between chromatin fragments was prevented by using low-salt conditions in all steps in the absence of bivalent cations. All histones, including H1, were present in stoichiometric amounts in this active chromatin fraction. Active nucleosomes showed a lower electrophoretic mobility than bulk nucleosomes in an acrylamide/agarose composite gel in the absence of Mg2+, but were selectively bound to the gel in the presence of this ion.

A fraction of mouse sperm chromatin is organized in nucleosomal hypersensitive domains enriched in retroposon DNA

1999 ◽  
Vol 112 (20) ◽  
pp. 3537-3548 ◽  
Author(s):  
C. Pittoggi ◽  
L. Renzi ◽  
G. Zaccagnini ◽  
D. Cimini ◽  
F. Degrassi ◽  
...  
Keyword(s):  
Nuclease Activity ◽  
Sperm Chromatin ◽  
Dorsal Margin ◽  
Chromosomal Dna ◽  
Active Chromatin ◽  
Immunofluorescence Analysis ◽  
Major Satellite ◽  
Chromatin Fraction ◽  
Sperm Nuclei ◽  
Endogenous Nuclease

We have characterized a nuclease hypersensitive chromatin fraction from murine spermatozoa. Endogenous nuclease activity can be induced in mouse epididymal spermatozoa by appropriate stimuli and cause the localized degradation of chromosomal DNA. Based on these observations, we have isolated nuclease hypersensitive chromatin regions released from spermatozoa in the supernatant of pelleted sperm cells, and have cloned and characterized the DNA. Gel electrophoresis of end-labelled released DNA fragments showed a typical nucleosomal distribution. Peripherally distributed nucleohistones were visualized by immunofluorescence in sperm nuclei, and histones were identified by western blot in sperm chromatin. Moreover, the released DNA is enriched in retroposon DNA from a variety of families. FISH and immunofluorescence analysis showed that retroposon DNA and nucleohistone chromatin co-localize and are both peripherically distributed in nuclei of spermatozoa. In contrast, a major satellite DNA probe, used for control, co-localizes with highly condensed chromatin in the central region of sperm nuclei. The nuclear Ran and RCC1 proteins were also visualized in the dorsal margin of sperm nuclei, and were abundantly released with the hypersensitive chromatin fraction. Together, these results indicate that nucleohistone chromatin fraction(s) with typical features of ‘active’ chromatin are present in murine spermatozoa, are hypersensitive to nuclease cleavage, enriched in retroposon DNA and organized in nucleosomal domains. These observations suggest that nucleohistone domains identify a fraction of the sperm genome which may be functional during early embryogenesis.

scholarly journals Nucleosomal histones of transcriptionally active/competent chromatin preferentially exchange with newly synthesized histones in quiescent chicken erythrocytes

1990 ◽  
Vol 271 (1) ◽  
pp. 67-73 ◽  
Author(s):  
M J Hendzel ◽  
J R Davie
Keyword(s):  
Cell Cycle ◽  
Active Component ◽  
Cell Cycle Phase ◽  
Chromatin Remodelling ◽  
Cycle Phase ◽  
Active Chromatin ◽  
Chromatin Domains ◽  
Chromatin Fraction ◽  
Chicken Erythrocytes

The incorporation of newly synthesized histones among various chromatin fraction isolated from non-replicating cell-cycle-phase-Go chicken immature erythrocytes was investigated. We find that newly synthesized erythroid-specific histone Hl variant H5, is incorporated randomly into chromatin. In contrast, newly synthesized nucleosomal histones H2A, H2A.Z, H2B, H3.3, and H4 are preferentially found in a fraction that is highly enriched in active/competent gene chromatin fragments and depleted in repressed gene chromatin. Moreover, ubiquitinated species of histones H2A and H2B and hyperacetylated species of H4 and H2B, which are complexed to active DNA, are labelled. These observations provide evidence that newly synthesized histones preferentially exchange with the nucleosomal histones of transcriptionally active/component chromatin domains. The results of this study suggest that nucleosomes of active chromatin may be inherently less stable than bulk nucleosomes in vivo and have implications for chromatin remodelling.

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