Different chromatin structures in Physarum polycephalum

Scheer, Ulrich; Zentgraf, Hanswalter; Sauer, Helmut W.

doi:10.1007/bf00399138

Cited by 28 publications

(7 citation statements)

References 39 publications

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“…Histone H3 has been localized to the surface of P1B/1C Phe the core particle (30) and appears to be the first component of the particle to be digested by trypsin in vitro (6). The nucleosomal structure in transcriptionally active chromatin is not disintegrated, only conformationally altered (52,58), as demonstrated, for example, by the accessibility of sulfhydryl groups in the center of histone H3 to SH reagents in active chromatin (1,47). Acetylation of lysine residues of core histones H3 and H4 correlates with this nucleosome alteration.…”

Section: Discussionmentioning

confidence: 99%

Foot-and-mouth disease virus protease 3C induces specific proteolytic cleavage of host cell histone H3

Falk

Grigera

Bergmann

et al. 1990

J Virol

157

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In foot-and-mouth disease virus (FMDV)-infected cells, the disappearance of nuclear protein histone H3 and the simultaneous appearance of a new chromatin-associated protein termed Pi can be observed (P. R. Grigera and S. G. Tisminetzky, Virology 136:10-19, 1984). We sequenced the amino terminus of protein Pi and showed that Pi derives from histone H3 by proteolytic cleavage. The 20 N-terminal amino acid residues of histone H3 are specifically cleaved off early during infection. Truncated histone H3 remains chromatin associated. In addition, we showed that the histone H3-Pi transition is catalyzed by the FMDV 3C protease. The only known function of the viral 3C protease was, until now, the processing of the viral polyprotein. The viral 3C protease is the only FMDV protein required to induce the histone H3-Pi transition, as well as being the only viral protein capable of cleaving histone H3. No viral precursor fusion protein is needed for this specific cleavage as was reported for the processing of the poliovirus P1 precursor polyprotein by 3C/D protease. As the deleted part of the histone H3 corresponds to the presumed regulatory domain involved in the regulation of transcriptionally active chromatin in eucaryotes, it seems possible that this specific cleavage of histone H3 is related to the host cell transcription shutoff reported for several picornaviruses.

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Section: Discussionmentioning

confidence: 99%

Foot-and-mouth disease virus protease 3C induces specific proteolytic cleavage of host cell histone H3

Falk

Grigera

Bergmann

et al. 1990

J Virol

157

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“…Chromatin of plasmodia in the G2-phase was spread according to (19) except that the 1% ethanolic phosphotungstic acid staining was omitted and the rotary shadowing was performed using platinum only.…”

Section: Electron Microspopymentioning

confidence: 99%

Processing in the external transcribed spacer of ribosomal RNA fromPhysarum polycephalum

Blum¹,

Pierron

Seebeck³

et al. 1986

Nucl Acids Res

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The rDNA of the myxomycete Physarum polycephalum is transcribed to give a 13.3 kb precursor of ribosomal RNA. At 1.7 kb downstream of the primary initiation site there is a processing site or a second initiation site. This site was studied by S1-mapping, DNA sequencing and electron microscopy. None of these methods could conclusively distinguish between the two formal possibilities. However, capping experiments indicate that rapid processing is taking place at this site rather than reinitiation. In addition, primary transcripts and processed molecules were assayed throughout the synchronous mitotic cycle. During all interphase stages newly initiated transcripts of rDNA and products of the first processing step are present in similar amounts, indicating control of initiation and not of maturation as being the main regulatory step for the accumulation of mature rRNAs. During the brief period of mitosis the level of newly initiated rRNA precursors is lowered.

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“…Another aspect of chromatin structure which bears on the regulation of transcription is a possible relation between the unfolding of the nucleosome core and the accessibility of DNA for transcription. Until now, the evidence in this direction has come mainly from electron microscopic studies of transcriptionally active chromatin (Foe et al, 1976;Scheer et al, 1981). These have revealed that transcriptionally active chromatin is often devoid of any visible nucleosome organization.…”

Section: Biological Implicationsmentioning

confidence: 99%

Elastic torsional strain in DNA within a fraction of SV40 minichromosomes: relation to transcriptionally active chromatin.

Luchnik¹,

Bakayev²,

Zbarsky³

et al. 1982

The EMBO Journal

135

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After treatment of SV40 minichromosomes with DNA topoisomerase I, the superhelicity in the bulk of the DNA extracted from minichromosomes is known to remain unchanged. However, we found that the DNA extracted from a small fraction of SV40 minichromosomes (2‐5%), was almost completely relaxed, and covalently closed as shown by agarose gel electrophoresis. Thus, the DNA in these 2‐5% of SV40 minichromosomes was probably torsionally strained (TS). The proportion of such TS minichromosomes is close to the estimated proportion of transcriptionally active minichromosomes. The distribution of the TS minichromosomes in sucrose gradient coincided with the distribution of transcriptionally active complexes. Both sedimented faster than the majority of minichromosomes. Furthermore, after treatment with topoisomerase I the relaxed minichromosomes could be quantitatively separated from the bulk of material by recentrifugation in a sucrose gradient. A major part of the endogenous RNA polymerase activity was recovered in the relaxed fraction. These data suggest that TS‐minichromosomes correspond to transcriptionally active chromatin. After relaxation with topoisomerase I the TS minichromosomes lacked histones.

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Different chromatin structures in Physarum polycephalum

Cited by 28 publications

References 39 publications

Foot-and-mouth disease virus protease 3C induces specific proteolytic cleavage of host cell histone H3

Foot-and-mouth disease virus protease 3C induces specific proteolytic cleavage of host cell histone H3

Processing in the external transcribed spacer of ribosomal RNA fromPhysarum polycephalum

Elastic torsional strain in DNA within a fraction of SV40 minichromosomes: relation to transcriptionally active chromatin.

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