Search results for "Micrococcal nuclease"
showing 10 items of 17 documents
Subtracting the sequence bias from partially digested MNase-seq data reveals a general contribution of TFIIS to nucleosome positioning.
2017
Background TFIIS stimulates RNA cleavage by RNA polymerase II and promotes the resolution of backtracking events. TFIIS acts in the chromatin context, but its contribution to the chromatin landscape has not yet been investigated. Co-transcriptional chromatin alterations include subtle changes in nucleosome positioning, like those expected to be elicited by TFIIS, which are elusive to detect. The most popular method to map nucleosomes involves intensive chromatin digestion by micrococcal nuclease (MNase). Maps based on these exhaustively digested samples miss any MNase-sensitive nucleosomes caused by transcription. In contrast, partial digestion approaches preserve such nucleosomes, but intr…
A low repeat length in oligodendrocyte chromatin
1985
Abstract: The behavior of oligodendrocyte chromatin after micrococcal nuclease digestion of nuclei was assayed in brains of rats of four different ages. During oligodendrocyte differentiation, a decreasing sensitivity of the chromatin to enzymatic attack was observed. On the other hand, the nucleosomal repeat length showed a slight tendency to increase during development. It is worth noting that even the highest values reported here for “oligodendrocyte’ chromatin repeat lengths are significantly lower than 200 base pairs, the value previously reported by others for “non‐astrocytic glia.” Copyright © 1985, Wiley Blackwell. All rights reserved
Identification and typing of food-borne Staphylococcus aureus by PCR-based techniques.
2005
Abstract The possibility of using PCR for rapid identification of food-borne Staphylococcus aureus isolates was evaluated as an alternative to the API-Staph system. A total of 158 strains, 15 S. aureus , 12 other staphylococcal species, and 131 isolates recovered from 164 food samples were studied. They were phenotypically characterized by API-Staph profiles and tested for PCR amplification with specific primers directed to thermonuclease ( nuc ) and enterotoxin ( sea to see ) genes. Disagreement between the PCR results and API-Staph identification was further assessed by the analysis of randomly amplified polymorphic DNA (RAPD) profiles obtained with three universal primers (M13, T3, and T…
Sliding-end-labelling
1986
Abstract A method, termed ‘sliding-end-labelling’, has been devised to avoid a frequent artifact in nucleosome positioning by indirect end labelling, namely the appearing of DNA fragments originated by two nuclease cuts, one of them lying within the region covered by the probe. The method is applied to the nucleosome positioning in the yeast SUC2 gene for invertase.
2′,5′-oligoadenylate synthetase from a lower invertebrate, the marine sponge Geodia cydonium, does not need dsRNA for its enzymatic activity
2002
AbstractRecently, the presence of 2′,5′-linked oligoadenylates and a high 2′,5′-oligoadenylate synthetase activity were discovered in a lower invertebrate, the marine sponge Geodia cydonium. It has been demonstrated that mammalian 2–5A synthetase isozymes require a dsRNA cofactor for their enzymatic activity. Our results show that, unlike mammalian 2–5A synthetases, the 2–5A synthetase from the sponge acts in a dsRNA-independent manner in vitro. A prolonged incubation of the G. cydonium extract with a high concentration of a micrococcal nuclease had no effect on the activity of the 2–5A synthetase. At the same time, the micrococcal nuclease was effective within 30 min in degrading dsRNA nee…
Chromatin structure of the yeast SUC2 promoter in regulatory mutants
1992
We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon derepression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. Thes…
Different micrococcal nuclease cleavage patterns characterize transcriptionally active and inactive sea-urchin histone genes.
1986
Micrococcal nuclease (MNase) and DNaseI have made a great contribution to our present understanding of the structural organization of the eucaryotic genome [l - 31. The enhanced sensitivity of active portions of the genome to DNaseI gave, in fact, the first indication of differences in the nucleoproteic arrangement of the transcribed as compared to the silent DNA regions [4]. The use of MNase, as a probe of the chromatin organization of specific genes in the active and inactive state, provided additional evidence for this and further showed that the packing of several coding segments of DNA in a regular array of nucleosomal particles is severely but reversibly affected by the transcriptiona…
Acetylated nucleosome assembly on telomeric DNAs
2003
Abstract The role of histone N-terminal domains on the thermodynamic stability of nucleosomes assembled on several different telomeric DNAs as well as on ‘average’ sequence DNA and on strong nucleosome positioning sequences, has been studied by competitive reconstitution. We find that histone tails hyperacetylation favors nucleosome formation, in a similar extent for all the examined sequences. On the contrary, removal of histone terminal domains by selective trypsinization causes a decrease of nucleosome stability which is smaller for telomeres compared to the other sequences examined, suggesting that telomeric sequences have only minor interactions with histone tails. Micrococcal nuclease…
Fine analysis of the chromatin structure of the yeast SUC2 gene and of its changes upon derepression. Comparison between the chromosomal and plasmid-…
1987
Micrococcal nuclease digestion has been used to investigate some fine details of the chromatin structure of the yeast SUC2 gene for invertase. Precisely positioned nucleosomes have been found on a 2 kb sequence from the 3' non-coding region, and four nucleosomes also seem to occupy fixed positions on the 5' flank. Eleven nucleosomes lie on the coding region, although their positioning is not as precise as in the flanks. When the gene is derepressed, these latter nucleosomes adopt a more open conformation and so do two of the nucleosomes positioned on the 5' flank. A dramatic change occurs in the 3' flank, whose involvement in the structural transitions of chromatin upon gene activation is p…
Rat CNS neurons are not yet programmed to shorten their chromatin repeat length at the end of fetal neurogenesis.
1986
Neurons from rat fetal cerebral hemispheres were grown in a synthetic medium (Maat medium), as previously described, for different periods of time. The repeat length of their chromatin was determined by micrococcal nuclease digestion and compared with that of neurons isolated from postnatal rat brain of corresponding ages. In contrast to the in vivo situation, we found that neurons, dissociated at the 16th gestational day and cultured in vitro, did not undergo the shortening of their chromatin repeat, thus indicating that, at the end of their mitotic cycles, they are not yet programmed to this event. © 1986.