The compaction pattern of the chromatin of trypanosomes

Hecker, Hermann; Gander, Eugen S.

doi:10.1111/j.1768-322x.1985.tb00368.x

Cited by 55 publications

(59 citation statements)

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“…The results obtained with 0-2 % glutaraldehyde were superior to those with the 'conventional' concentration of 0-1 % (Thoma et al 1979;Hecker & Gander, 1985). Chromatin prepared with 0 -5 % glutaraldehyde showed an identical condensation behaviour to the one fixed with 0-2 %.…”

Section: Discussionmentioning

confidence: 77%

“…Approximately 10 g liver from rats was homogenized in the presence of 1 mM phenylmethylsulphonylfluoride (PMSF) and the nuclei were purified by centrifugation through sucrose cushions (Thoma, Roller & Klug, 1979;Hecker & Gander, 1985). T. b. brucei STIB 345 AB were harvested, and 2-3 x 10 10 exponentially growing procyclic cells resuspended in hypotonic buffer containing 0-5 M 2-methyl-2,4-pentandiol (hexylene glycol), 2-5 mM CaCl 2 , 1 mM PMSF.…”

Section: Purification Of Nucleimentioning

confidence: 99%

“…T. b. brucei STIB 345 AB were harvested, and 2-3 x 10 10 exponentially growing procyclic cells resuspended in hypotonic buffer containing 0-5 M 2-methyl-2,4-pentandiol (hexylene glycol), 2-5 mM CaCl 2 , 1 mM PMSF. They were lysed by nitrogen cavitation at 25 bar (Shapiro & Doxsey, 1982), vortexed for 30 s and the isolated nuclei were washed in 90 mM suspension buffer, pH 7-4, containing 0 1 mM disodium ethylendiaminetetraacetic acid (Na 2 EDTA) (Thoma et al 1979;Hecker & Gander, 1985).…”

Section: Purification Of Nucleimentioning

confidence: 99%

“…Insoluble material was removed by centrifugation (Thoma et al 1979;Hecker & Gander, 1985). The preparation of soluble chromatin was identical for procyclic culture forms and for bloodstream forms.…”

Section: Preparation Of Soluble Chromatinmentioning

confidence: 99%

“…However, the nucleosomes were spaced irregularly and no condensation into a typical 30 nm fibre took place under experimental conditions. The nuclear chromatin was digested rapidly by micrococcal nuclease, and the interactions between DNA and proteins were relatively weak and were easily destabilized under experimental conditions, which are normally used for the isolation of chromatin from higher eukaryotes (Hecker & Gander, 1985;Hecker et al 1989;Bender, Betschart & Hecker, 1992c). In addition, no histone HI could be demonstrated (Hecker & Gander, 1985 ;Hecker et al 1989).…”

Section: Introductionmentioning

confidence: 99%

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Trypanosoma brucei brucei: differences in the nuclear chromatin of bloodstream forms and procyclic culture forms

et al. 1993

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SUMMARYNucleosome filaments of two stages of the life-cycle of Trypanosoma brucei brucei, namely bloodstream forms and procyclic culture forms, were investigated by electron microscopy. Chromatin of bloodstream forms showed a salt-dependent condensation. The level of condensation was higher than that shown by chromatin from procyclic culture forms, but 30 nm fibres as formed in rat liver chromatin preparations were not found. Analysis of histones provided new evidence for the existence of HI-like proteins, which comigrated in the region of the core histones in SDS-PAGE and in front of the core histones in Triton acid urea gels. Differences were found between the HI-like proteins of the two trypanosome stages as well as between the core histones in their amount, number of bands and banding pattern. It can be concluded that T. b. brucei contains a full set of histones, including HI-like proteins, and that the poor condensation of its chromatin is not due to the absence of H1, but most probably due to histone-DNA interaction being weak. It is obvious that structural and functional differences of the chromatin exist not only between T. b. brucei and higher eukaryotes, but also between various stages of the life-cycle of the parasite. It is therefore not adequate to investigate the chromatin only of the procyclic culture forms as a model for all stages of the life-cycle of T. b. brucei.

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Section: Discussionmentioning

confidence: 77%

Section: Purification Of Nucleimentioning

confidence: 99%

Section: Purification Of Nucleimentioning

confidence: 99%

Section: Preparation Of Soluble Chromatinmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Trypanosoma brucei brucei: differences in the nuclear chromatin of bloodstream forms and procyclic culture forms

et al. 1993

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Presence of an unusually high concentration of an ubiquitinated histone-like protein inTrypanosoma cruzi

1997

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The conjugation of ubiquitin to histones H2A and H2B has been established in higher eukaryotes and has been related to changes in chromatin organization. In Trypanosoma cruzi, no condensation of chromatin occurs during mitosis. In order to determine the presence of histone ubiquitination in T. cruzi epimastigotes, histones were extracted from chromatin and analyzed by three electrophoretic systems: acid-urea, triton-acid-urea and sodium-dodecyl-sulphate polyacrylamide gel. The immunochemical detection of ubiquitin-histone conjugates by Western blotting showed a strong reaction with a slow migrating band of M(r) 19 kDa. The high percentage of ubiquitin-histone conjugates present in T. cruzi chromatin may be related to the inability of this parasite to condense chromatin into a 30 nm fiber.

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Differences in the nuclear chromatin among various stages of the life cycle of Trypanosoma cruzi

Spadiliero

Sánchez

Slezynger

et al. 2002

J of Cellular Biochemistry

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Trypanosoma cruzi is the etiological agent of Chagas. Although the nuclear chromatin of this parasite is organized in the form of nucleosome filaments, its chromatin is physically and enzymatically fragile, and no condensation into chromosomes occurs during mitosis. All previous investigations have been carried out with epimastigote form in its proliferate stage. It is not known whether these differences in chromatin structure are also found in the non-proliferate stationary epimastigote forms and in tissue derived trypomastigotes. Our results confirm that chromatin of logarithmic epimastigotes presents limited compaction when increasing salt concentrations from 1 to 100 mM NaCl, and no 30-nm fibers were formed. Contrary to these results, non-proliferative forms of the parasites showed a pattern of compactation similar to that observed in rat liver chromatin, where solenoids of 30-nm fibers are formed at 100-mM NaCl. In accordance with these results, digestion of the nuclear chromatin with DNase I revealed that the chromatin of logarithmic phase epimastigotes was more accessible to the enzyme. We conclude from these results that structural differences in the chromatin exist not only between T. cruzi and higher eukaryotes but also among various forms of the parasite. The functional significance of these differences are currently under investigation.

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The compaction pattern of the chromatin of trypanosomes

Cited by 55 publications

References 0 publications

Trypanosoma brucei brucei: differences in the nuclear chromatin of bloodstream forms and procyclic culture forms

Trypanosoma brucei brucei: differences in the nuclear chromatin of bloodstream forms and procyclic culture forms

Presence of an unusually high concentration of an ubiquitinated histone-like protein inTrypanosoma cruzi

Differences in the nuclear chromatin among various stages of the life cycle of Trypanosoma cruzi

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