Molecular basis of control of mitotic cell division in eukaryotes

Bradbury, E. Morton; Inglis, R. J.; Matthews, Harry R.; Langan, Thomas A.

doi:10.1038/249553a0

Cited by 188 publications

(43 citation statements)

References 21 publications

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“…Our findings of extensive phosphorylation of F1 in macronuclei coupled with the absence of F1 in micronuclei would seem to argue against the recent suggestion that phosphorylation of F1 is an important step in the initiation of mitosis (21,41). However, since macronuclei control the vegetative functions of Tetrahymena, it is still possible that phosphorylation of F1 plays some role in the control of cell divi-sion.…”

Section: Discussioncontrasting

confidence: 51%

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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Section: Discussioncontrasting

confidence: 51%

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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“…Histone H1 has been implicated in the control of cell division in the true slime mould P. polycephalum [22], and Osborn and Ashworth therefore conclude that the basic nucleoproteins of D. discoideum are more directly involved in the regulation of cell division rather than cell differentiation.…”

Section: Basic Nucleoproteins In Dividing and Differentiating Cellsmentioning

confidence: 99%

Further Studies on Basic Nucleoproteins from the Cellular Slime Mold Dictyostelium discoideum

Charlesworth

Parish

1977

Eur J Biochem

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The nuclei from Dictyostelium discoideum were isolated using a number of detergents. Microscopically clean and intact nuclei were obtained using Kyro EOB, Cemulsol NPT 12 and Triton X-100. While density gradient purification of Kyro-EOB-isolated nuclei led to some loss of basic nucleoproteins, Triton and Cemulsol-isolated nuclei gave relatively consistent patterns of basic nucleoproteins. The variabilities are discussed.No reproducible differences were found between basic nucleoproteins of vegetative and differentiating cells.The basic nucleoproteins were separated on sodium dodecylsulfate as well as acid/urea gels and compared with calf thymus histones. The perchloric-acid-soluble protein (fraction 1) which comigrates with histone H1 on acid/urea gels migrates faster than H1 on dodecylsulfate gels ( M , 19000-20000). The ethanol/HCl fraction ('arginine-rich') contained most of bands 3 and 4 and all of band 5 ; the latter comigrating with H4 on acid/urea gels.The amino acid compositions of whole basic nucleoprotein, fraction 1 protein and the ethanol/ HC1-soluble fraction were determined. The whole basic nucleoprotein contained a high proportion of arginine and lysine, although like many lower eukaryotes the basic/acidic amino acid ratio was relatively low (1.18). The ethanoliHC1-soluble fraction contained about 13.7 mol lysine and 9 mol arginine per 100 mol total residues compared 9.6 and 12 mo1/100 mol respectively in a similar fraction from calf thymus histones.The fraction 1 protein is a lysine-rich protein, but contains more arginine and less lysine than calf thymus H1. Furthermore, it contains a much higher content of acidic (or amide) residues than H1. Hence, it resembles the two lysine-rich basic nucleoproteins of Physarum polycephalum.Tryptic peptide maps of fraction 1 protein and H1 were compared. Some 14 spots were superimposable and one group of five small, highly charged peptides showed a striking correspondence. The possibility that they occur in a conserved region of the protein involved in DNA binding is considered. The similarity between fraction 1 protein and the calf thymus highmobility group proteins is discussed.We have previously described the isolation of nuclei and basic nucleoproteins from the cellular slime mould Dictyostelium discoideum [l]. In this paper we examine more closely the effects of nuclei isolation procedures on the pattern of basic proteins. In particular, since there are conflicting reports concerning the effects of Triton X-100 on nuclei [2,3], we decided to see whether somewhat milder detergents offered any advantages. Modifications of our original method for the isolation of nuclei are also described. In addition we have separated the basic nucleoproteins on sodium dodecylsulfate as well as acid/urea gels.Recently, Osborn and Ashworth [4] reported that there was a difference between the basic nucleoproteins of growing and differentiating cells and we have checked this possibility.We have as yet been unable to separate the individual basic nucleoproteins using methods ...

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“…1973; Gurley et al, 1978) or in initiating chromosome condensation (Matsumoto et al, 1980;Bradbury et al, 1974;Inglis et al, 1976). Phosphorylation leads to an alteration of the charge of modified serine and threonine residues and may thus modulate histone-DNA interactions.…”

Section: Introductionmentioning

confidence: 99%

Use of histone antibodies for studying chromatin topography and the phosphorylation of chromatin subunits.

Muller¹,

Mazen²,

Martinage³

et al. 1984

The EMBO Journal

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Polyclonal and monoclonal antibodies specific for histones as well as sera directed against synthetic peptides of histones were used to probe the topography of chromatin subunits. In native chromatin, the regions corresponding to residues 130 -135 of H3 and 6-18 of H2B were found to be exposed and able to interact with antibodies whereas the regions 26-35 and 36-43 of H2B and 80-89 and 85-102 of H4 were not. In vitro phosphorylation of H3 and H5 in native chromatin or of H3 in H1/H5-depleted chromatin led to a marked drop in the binding of antibodies specific for residues 130-135 of H3 and 6-18 of H2B. Phosphorylation of H1/H5-depleted chromatin also altered the degree of exposure of certain H2A epitopes but it did not affect the surface accessibility of residues 1-11 of H2B.

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Molecular basis of control of mitotic cell division in eukaryotes

Cited by 188 publications

References 21 publications

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

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

Further Studies on Basic Nucleoproteins from the Cellular Slime Mold Dictyostelium discoideum

Use of histone antibodies for studying chromatin topography and the phosphorylation of chromatin subunits.

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