Histone synthesis and phosphorylation in regenerating rat liver

Gutierrez‐Cernosek, Rose Mary; Hnilica, Lubomir S.

doi:10.1016/0005-2787(71)90682-4

Cited by 34 publications

(4 citation statements)

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“…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) was also observed in Tetrahymena. Recent studies of histone phosphorylation in different cells have led to the various suggestions that phosphorylation of histone F1 may be involved in the alteration of chromatin structure during interphase (17), in chromosome replication (18,19), in the sorting out of newly synthesized chromatids during S-phase (20), in the process of mitotic chromosome condensation (21)(22)(23) or in the control of genetic activity (24)(25)(26). Since MATERIALS AND METHODS Cell Culture.…”

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confidence: 99%

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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confidence: 99%

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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“…Protein phosphokinases with different substrate specificity have been found [5,6] and histone phosphorylation has been particularly implicated in gene activation through increased template activity [7]. In fact, the increased rate of nucleoprotein phosphorylation is concomitant with an active cell division like that occurring e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Protein phosphorylation is a widespread phenomenom [l] involving, among others, such distinct cell functions as enzyme conversions [2] , changes ' in membrane permeability [3], and regulation of RNA transcription [4]. Protein phosphokinases with different substrate specificity have been found [5,6] and histone phosphorylation has been particularly implicated in gene activation through increased template activity [7]. In fact, the increased rate of nucleoprotein phosphorylation is concomitant with an active cell division like that occurring e.g.…”

Section: Introductionmentioning

confidence: 99%

Protein phosphokinases of chick muscle: Changes during embryonic development

Piras¹,

Staneloni²,

Leiderman³

et al. 1972

FEBS Letters

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“…The lysine-rich histone, H1, has been implicated in a variety of nuclear processes. Recent evidence links H1 and its phosphorylation in a number of cell types with the alteration of the structure of interphase chromatin throughout the cell cycle (16,18), including the conversion of nonproliferating cells to proliferating ones (17), rates of cell replication (1,2,28), chromosome condensation during mitosis (4,5,25), premitotic separation of sister chromatids (26), and the control of genetic activity (19,24,27).…”

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Immunofluorescence evidence for the absence of histone H1 in a mitotically dividing, genetically inactive nucleus.

Johmann¹,

Gorovsky²

1976

The Journal of Cell Biology

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Antibodies directed against whole histone and purified lysine-rich histone H1extracted from isolated macronuclei of the ciliate Tetrahymena were obtained and conjugated to fluorescein isothiocyanate. The fluorescein-antibody conjugates were used to directly label Tetrahymena cells. Both macro-and micronuclei were visibly fluorescent in cells stained with anti-whole histone conjugate. However, the anti-H1 conjugate only labeled macronuclei. This in situ demonstration of the lack of positive immunofluorescent staining of micronuclei with anti-H 1 conjugate provides further evidence for the absence of H1 in the genetically inactive, mitotically dividing Tetrahymena micronucleus.The lysine-rich histone, H1, has been implicated in a variety of nuclear processes. Recent evidence links H1 and its phosphorylation in a number of cell types with the alteration of the structure of interphase chromatin throughout the cell cycle (16,18), including the conversion of nonproliferating cells to proliferating ones (17), rates of cell replication (1, 2, 28), chromosome condensation during mitosis (4,5,25), premitotic separation of sister chromatids (26), and the control of genetic activity (19,24,27).Studies done on the histones of the ciliate Tetrahymena have indicated that H1 is present, in multiple molecular species each capable of being phosphorylated, in the amitotically dividing, genetically active macronucleus of this organism (14). 1 However, the mitotically dividing, genetically inactive micronucleus apparently lacks histone H1 (12). These findings impose certain limits 1 Johmann, C. A., and M. A. Gorovsky. Manuscript in preparation.on the speculations concerning the biological role(s) of H1 in chromatin structure and function (12, 13).Since histone H1 is highly susceptible to proteolyric degradation (3, 30) and is easily dissociated from chromatin (10), the absence of H1 in isolated Tetrahymena micronuclei conceivably could be the result of a preparative artifact. Data obtained by Gorovsky and Keevert (12) argue strongly against such artifactual loss of H1 from micronuclei. However, studies done on isolated nuclei and chromatin cannot unequivocally dismiss the possibility that in vivo micronuclei contain H1. Thus, an immunofluorescence analysis was undertaken to determine the presence or absence of histone H1 in the macro-and micronuclei of Tetrahymena strain BVII. Antibodies directed against BVII whole histone and purified H1 were isolated, conjugated to fluorescein isothiocyanate, and used to stain BVII cells. The results confirm our previous conclusion that micronuclei lack histone H1 (12).

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Histone synthesis and phosphorylation in regenerating rat liver

Cited by 34 publications

References 38 publications

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

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

Protein phosphokinases of chick muscle: Changes during embryonic development

Immunofluorescence evidence for the absence of histone H1 in a mitotically dividing, genetically inactive nucleus.

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