Changes in chromatin and the phosphorylation of nuclear proteins during heat shock of Achlya ambisexualis.

Pekkala, David H.; Heath, Bobby J.; Silver, Julie C.

doi:10.1128/mcb.4.7.1198

Cited by 38 publications

(18 citation statements)

References 37 publications

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“…The chromatin in nuclei condenses (20), whereas nucleoli disperse (13, 24). Bundles of actin filaments also form within the nuclei (20,23), and in the cytoplasm, the intermediate filament network collapses onto the nucleus (23).The effects of heat shock on intact organisms or tissues have been less well characterized. Embryos are highly susceptible to heat shock, however, as they often develop severe abnormalities if exposed to elevated temperatures during critical periods of their development.…”

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The effects of heat shock on the morphology and protein synthesis of the epidermis of Xenopus laevis larvae.

Nickells

Cavey

Browder

1988

The Journal of Cell Biology

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Abstract. By scanning electron microscopy, we have observed that a 20-min heat shock at 37~ although not lethal, causes extensive damage to the epidermis of 30-h and 2-d (post-fertilization) Xenopus laevis larvae. The primary effects of heat shock are the apical swelling of the epidermal cells, giving the epidermis a "cobblestone" appearance, and the selective shedding of the ciliated cells. The shed cells may be cell fragments, however, because some of them are anucleate. Shed cells also exhibit the enriched synthesis of a group of heat shock proteins of 62,000 D molecular weight, suggesting that these proteins are specific to the shed cells. Prolonged heat shock of these larvae (i.e., 30 min at 37~ results in the complete disintegration of the epidermis, followed by larval death. At later stages of development (3-d and 4-d post-fertilization), the epidermis becomes more resistant to heatinduced damage inflicted by a 20-min heat shock. This increase in resistance coincides with the development of large secretory cells and the loss of ciliated cells in the epidermis and thus parallels a change in the state of histological differentiation.T HE effect of heat shock on the physiology and metabolism of cells has been extensively studied. Most investigations have concentrated on analyzing the molecular responses of cells to thermal stress. During heat shock, cells selectively synthesize heat shock proteins (hsps), ~ which are believed to enhance their ability to survive at the higher temperature (for reviews see 2, 14, 19).Heat shock can cause extensive cellular damage, particularly to membranous structures. These effects have been examined at the ultrastructural level and include the dispersal of the Golgi apparatus (23) and endoplasmic reticulum (3) and the swelling of mitochondria (23), which apparently lose the ability to function properly (12; for review see 11). The plasma membrane is also affected by heat shock, exhibiting increases in fluidity (13), loss of active transport activity (4) and formation of lesions large enough to allow the passage of small molecules (for review see 19). Nonmembranous structures also suffer heat-induced damage. The chromatin in nuclei condenses (20), whereas nucleoli disperse (13, 24). Bundles of actin filaments also form within the nuclei (20,23), and in the cytoplasm, the intermediate filament network collapses onto the nucleus (23).The effects of heat shock on intact organisms or tissues have been less well characterized. Embryos are highly susceptible to heat shock, however, as they often develop severe abnormalities if exposed to elevated temperatures during critical periods of their development. These effects are exemplified by mammalian embryos, which are particularly susceptible to heat-induced defects of the central nervous system 1. Abbreviation used in this paper: hsp, heat shock protein.(22), and by Drosophila larvae, which can be induced by heat shock to develop phenocopies (15). How heat shock effects developing embryos is uncertain, although some lines of evidence ...

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The effects of heat shock on the morphology and protein synthesis of the epidermis of Xenopus laevis larvae.

Nickells

Cavey

Browder

1988

The Journal of Cell Biology

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“…One of the prominent antheridiolinduced proteins exhibits a molecular weight of 85,000 and was found both in the nuclear and cytoplasmic fractions of antheridiol-treated cells (10). This protein seemed very similar in electrophoretic behavior to the Achlya 85-kilodalton (kDa) heat shock protein (49), which is one of the several characteristic heat shock proteins observed in A. ambisexualis (33,34,49). We have therefore investigated the relationship between these two 85-kDa proteins and their regulation by both heat shock and by the steroid hormone antheridiol.…”

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Steroid hormone regulation of the Achlya ambisexualis 85-kilodalton heat shock protein, a component of the Achlya steroid receptor complex.

Brunt¹,

Riehl²,

Silver³

1990

Mol. Cell. Biol.

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The steroid hormone antheridiol regulates sexual development in the fungus Achlya ambisexualis. Analyses of in vivo-labeled proteins from hormone-treated cells revealed that one of the characteristic antheridiolinduced proteins appeared to be very similar to the Achlya 85-kilodalton (kDa) heat shock protein. Analysis of in vitro translation products of RNA isolated from control, heat-shocked, or hormone-treated cells demonstrated an increased accumulation of mRNA encoding a similar 85-kDa protein in both the heat-shocked and hormone-treated cells. Northern (RNA) blot analyses with a Drosophila melanogaster hsp83 probe indicated that a mRNA species of approximately 2.8 kilobases was substantially enriched in both heat-shocked and hormone-treated cells. The monoclonal antibody AC88, which recognizes the non-hormone-binding component of the Achlya steroid receptor, cross-reacted with Achlya hsp85 in cytosols from heat-shocked cells. This monoclonal antibody also recognized both the hormone-induced and heat shock-induced 85-kDa in vitro translation products. Taken together, these data suggest that similar or identical 85-kDa proteins are independently regulated by the steroid hormone antheridiol and by heat shock and that this protein is part of the Achlya steroid receptor complex. Our results demonstrate that the association of hsp9O family proteins with steroid receptors observed in mammals and birds extends also to the eucaryotic microbes and suggest that this association may have evolved early in steroid-responsive systems.The water mold Achlya ambisexualis is a eucaryotic, filamentous fungus in which sexual reproduction is regulated by well-characterized steroid hormones (4,22,54). There are at least two mating types in A. ambisexualis, and these are usually referred to as male and female. Each of these mating types produces a specific fungal steroid hormone which is secreted into the medium and which mediates both chemotropic and developmental changes in cells of the opposite mating type. In this respect, the Achlya steroids act as both pheromones and hormones.The fungal steroid hormone antheridiol, normally produced by female strains of A. ambisexualis, has been isolated (30) and characterized (2). Studies in our laboratory have focused on the early developmental events which occur when antheridiol is added to vegetatively growing cultures of the male mating type, strain E87 (9-11, 48). In E87, one of the earliest developmental events seen at the morphological level after treatment of cells with the hormone is the formation of distinct structures called antheridial branches (3). Both the time of onset of branching and the percent of hyphae branched are directly related to the amount of hormone added (9, 30). Thus, the response is very synchronous, and a high percentage of the hyphae is target tissue for the hormone. For these reasons, A. ambisexualis represents an interesting system in which to investigate both the mechanism of action of steroid hormones and the evolution of steroid hormone systems.In previou...

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“…Heat-shocked cells present strong alterations of chromatin structures, exhibiting a markedly condensed chromatin (Iliakis and Pantelias 1989;Warters et al 1986), a weaker sensitivity to DNaseI (Pekkala et al 1984) as well as a weaker sensitivity to diffusible mitotic factors (Iliakis and Pantelias 1989). One of the described molecular effects of heat shock on chromatin components is increased histone H1 phosphorylation in vivo (Glover et al 1981).…”

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Heat‐shock and related stress enhance RNA polymerase II C‐terminal‐domain kinase activity in HeLa cell extracts

Legagneux

Morange

Bensaude

1990

European Journal of Biochemistry

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Changes in protein kinase activities are thought to contribute to the alteration of gene expression after heat shock and related stresses. In an attempt to identify enzymes which might be involved in both chromatin structure modification and transcriptional switch in heat-shocked cells, we have studied protein kinase activities in heatshocked cell lysates with two exogenous substrates : a tetramer of a heptapeptide (heptapeptide 4) corresponding to the RNA polymerase I1 C-terminal domain (CTD), and the histone H1. Heat-shock and arsenite stress were found to stimulate strongly CTD kinase activity. H1 kinase activity was also stimulated but more weakly. Stimulation of CTD and H1 kinases occurs mainly at the early phase of recovery and by a process which is independent of protein synthesis. The stress-induced H1 kinase is shown to contain a molecule related to the mitotic-promoting factor (MPF) Cdc2 component. On the other hand, though Cdc2-related protein has also been reported to be part of a CTD kinase complex, we show that the stress-induced CTD kinase activity corresponds to a distinct entity. It is proposed that stress activation of CTD kinase might be involved in changing the specificity of RNA polymeiase 11.-Alterations of cellular metabolism by heat shock can be mediated by changes in the activities of protein kinase and protein phosphatase. For example, shut-off by heat shock of most messenger RNA translation, except that of mRNAs coding for heat-shock proteins, is correlated with well-documented changes in the phosphorylation state of ribosomal proteins and initiation factors. Ribosomal protein S6 (Glover 1982; Kennedy et al. 1984;Olsen et al. 1983) and initiation factors elF4B (Duncan and Hershey 1984) and elF4F (Duncan et al. 1987) are dephosphorylated whereas the initiation factor elF2a (Duncan and Hershey 1984) is hyperphosphorylated by heme-controlled repressor kinase in heat-shocked cells or reticulocyte lysates (Bonanou-Tzedaki et al. 1981 ; De Benedetti and Baglioni 1986). Another early effect of heat shock is the shut-off of gene transcription, except that of genes encoding the heat-shock proteins (HSPs) which is specifically stimulated (Lindquist 1986). This specific heat-shock response involves the activation, at least partially by phosphorylation, of a heat-shock gene transcription factor (Sorger and Pelham 1988). The kinase responsible for phosphorylation of this factor has not yet been identified. Simultaneously, RNA polymerase I1 has been found to be redistributed on Drosophila chromosomes, being removed from most non-heat-shock loci and concentrated on heat-shock loci (Jamrich et al. 1977).

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Changes in chromatin and the phosphorylation of nuclear proteins during heat shock of Achlya ambisexualis.

Cited by 38 publications

References 37 publications

The effects of heat shock on the morphology and protein synthesis of the epidermis of Xenopus laevis larvae.

The effects of heat shock on the morphology and protein synthesis of the epidermis of Xenopus laevis larvae.

Steroid hormone regulation of the Achlya ambisexualis 85-kilodalton heat shock protein, a component of the Achlya steroid receptor complex.

Heat‐shock and related stress enhance RNA polymerase II C‐terminal‐domain kinase activity in HeLa cell extracts

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