STUDIES ON HISTONE FRACTION F2A1 IN MACRO- AND MICRONUCLEI OF <i>TETRAHYMENA PYRIFORMIS </i>

Gorovsky, Martin A.; Pleger, Gloria L.; Keevert, Josephine Bowen; Johmann, Carol A.

doi:10.1083/jcb.57.3.773

Cited by 83 publications

(31 citation statements)

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“…In previous studies we have shown that the antibody recognizes its antigen in nucleosomes (30) and in whole chromatin by in situ immunofluorescence (37). We have already shown that hyperacetylated forms of H4 histone can be found in macronuclei of vegetatively growing cells (37) of T. Thermophila and this is in agreement with electrophoretic analyses where the patterns of histones extracted from macro-and micronuclei are compared (21). This paper gives details of acetylation processes during the development of the new macro-and micronuclei in conjugating Tetrahymena thermophila.…”

supporting

confidence: 73%

Histone acetylation in conjugating Tetrahymena thermophila [published erratum appears in J Cell Biol 1989 Dec;109(6 Pt 1):3214-7]

Pfeffer¹

1989

The Journal of Cell Biology

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Abstract. We have monitored histone acetylation during conjugation of the ciliated protozoan Tetrahymena thermophila using antibodies against the tetraacetylated form of H4 histone (Pfeffer, U., N. Ferrari, and G. Vidali. 1986. J. Biol. Chem. 261:2496-2498. During meiosis, the three prezygotic divisions, fertilization, and the first postzygotic division, micronuclei, do not contain highly acetylated forms of H4 histone. However, after the second postzygotic division, when anteriorly located micronuclei begin to develop into new macronuclei, they are strongly stained by the anti-tetraacetylated H4 histone antibody. In the old macronucleus, histones are actively deacetylated when it has ceased to transcribe but before it is eliminated. Histone acetylation processes analyzed here appear to be correlated to the commitment to transcription rather than to the transcription process itself. This is in good correlation with evidence we have obtained in chick erythrocyte nuclei during reactivation upon fusion with mammalian cells (Pfeffer, U., N. Ferrari, E Tosetti, and G. Vidali. 1988. Exp. Cell Res. 178:25-30). Furthermore, it becomes clear from our data that histone acetylation occurs in close correlation to the position of nuclei within the cytoplasm of T. thermophila.Mechanisms that control differential histone acetylation and deacetylation are discussed.S INCE the original observation, histone acetylation has been correlated to transcription and considerable evidence has accumulated indicating that this reversible postsynthetic modification of lysine residues in the aminoterminal portion of core histones plays a key role in the regulation of gene expression (for a review see reference 2).Different methods have been developed to fractionate chromatin depending on its transcriptional activity and accordingly, it has been found that fractions containing actively transcribed genes were enriched in highly acetylated histones (1,17,33). Recent analyses using anti-acetyl-lysine antibodies have established that a given gene is associated with highly acetylated histones when it is transcribed (23), although it cannot be ruled out that genes competent to be transcribed, but inactive at the moment of analysis, may also contain acetylated histones.Nucleosomes undergo reversible conformational changes during transcriptional activation (10, 32), histones are absent from promoter sequences of active genes (25), nucleosomes inhibit initiation of transcription but do not inhibit elongation of initiated transcripts (27, 28) and at least H4 histone is retained on a highly transcribed gene (35). The contact points between nucleosomal DNA and H4 histone have been analyzed and a highly basic cluster in the amino-terminal portion has been shown to be involved in sharp bending of the DNA double helix (18). Interestingly, this cluster encompasses lysine at position 16 which is the first to be acetylated in vivo in calf thymus (15) and, moreover, this region is in close contact to a site 55-65 bp from the end of the nucleosomal DNA, which ...

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supporting

confidence: 73%

Histone acetylation in conjugating Tetrahymena thermophila [published erratum appears in J Cell Biol 1989 Dec;109(6 Pt 1):3214-7]

Pfeffer¹

1989

The Journal of Cell Biology

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“…Most of the positive experimental indications for the postulated correlation are indirect in the sense that increased histone acetylation was observed concomitant with enhanced transcriptional activity (24)(25)(26)(27)(28)(29). It has also been shown, that susceptibility of chromatin to DNase I, which preferentially digests transcriptionally active chromatin (30), is associated with chromatin regions enriched with highly acetylated histones (31)(32)(33)).…”

Section: Discussionmentioning

confidence: 99%

RNA polymerase activity and template activity of chromatin after butyrate induced hyperacetylation of histones inPhysarum

Loidl¹,

Loidl²,

Puschendorf³

et al. 1984

Nucl Acids Res

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“…Nuclei were isolated as described (27,28). Chromatin was isolated by a modification of the method of Panyim et al (29).…”

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confidence: 99%

“…Thus, the relationship between the rate of cell replication and the extent of phosphorylation of histone F1 observed in a variety of other cell types (11)(12)(13)(14)(15)(16) MATERIALS AND METHODS Cell Culture. Tetrahymena pyriformis, strains WH-6 (Syngen 1, mating type I; a micronucleate strain) and GL (an amicronucleate strain), were cultured as described (27).…”

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confidence: 99%

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Absence of histone F1 in a mitotically dividing, genetically inactive nucleus.

Gorovsky¹,

Keevert²

1975

Proc. Natl. Acad. Sci. U.S.A.

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Histones were extracted from macro-and micronuclear chromatin of the ciliated protozoan Tetrahymena pyriformis. Conditions that resulted in macronuclear chromatin containing large amounts of histone F1 yielded micronuclear chromatin in which this histone was absent. Evidence is presented indicating that the absence of F1 from micronuclei is not a preparative artifact and that histone F1 is replaced by other tistone fractions. Since micronuclei divide mitotically, while macronuclei divide amitotically, these results suggest that histone F1 and its phosphorylation do not play an indispensable role in the process of mitotic chromosome condensation, in chromosome replication, or in the separation of newly synthesized chromatids. Like most ciliated protozoans, the vegetative cells of Tetrahymena pyriformis contain a macro-and a micronucleus. These two nuclei are formed from the daughter products of a single mitotic division during the sexual process of conjugation. It is likely, therefore, that they contain the same, or closely related, genetic information. In spite of their common origin and the fact that they reside in the same cytoplasmic millieu, macro-and micronuclei differ considerably in their structure and function (see ref. 1 for review). For example, macronuclei divide amitotically, with no sign of mitotic chromosomes; micronuclei divide mitotically (2-7). In addition, the two nuclei differ greatly in their genetic activity. Macronuclei are sites of intense RNA synthesis while micronuclei synthesize little, if any, detectable RNA (8, 9).We have recently reported that the macronucleus of Tetrahymena contains a histone with properties similar to those of histone F1 of higher organisms (10). Macronuclear F1 isolated from rapidly growing cells was found to be highly phosphorylated, while histones isolated from slowly growing cells contained only small amounts of phosphorylated FL. Thus, the relationship between the rate of cell replication and the extent of phosphorylation of histone F1 observed in a variety of other cell types (11)(12)(13)(14)(15)(16) MATERIALS AND METHODS Cell Culture. Tetrahymena pyriformis, strains WH-6 (Syngen 1, mating type I; a micronucleate strain) and GL (an amicronucleate strain), were cultured as described (27).Isolation of Nuclei and Chromatin. Nuclei were isolated as described (27,28). Chromatin was isolated by a modification of the method of Panyim et al. (29). Chromatin deficient in histone fraction F1 was prepared by washing isolated nuclei repeatedly in 0.5 M NaCl. This treatment was found to remove most of histone F1 from macronuclei while extracting little of the other histone fractions.Isolation of Histones. Histones were isolated from whole nuclei or from chromatin by extraction with either 2.4 M urea/0.2 M H2SO4 or with 0.2 M H2SO4 (10, 27).Thermal Denaturation of Isolated Chromatin. Solubilized macro-or micronuclear chromatin was fixed in 0.91% formaldehyde for at least 15 hr and then dialyzed for at least 5 hr against three changes (100 volumes each) of 0.2 mM ...

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STUDIES ON HISTONE FRACTION F2A1 IN MACRO- AND MICRONUCLEI OF TETRAHYMENA PYRIFORMIS

Cited by 83 publications

References 31 publications

Histone acetylation in conjugating Tetrahymena thermophila [published erratum appears in J Cell Biol 1989 Dec;109(6 Pt 1):3214-7]

Histone acetylation in conjugating Tetrahymena thermophila [published erratum appears in J Cell Biol 1989 Dec;109(6 Pt 1):3214-7]

RNA polymerase activity and template activity of chromatin after butyrate induced hyperacetylation of histones inPhysarum

Absence of histone F1 in a mitotically dividing, genetically inactive nucleus.

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