EFFECTS OF DIVISION-SYNCHRONIZING HYPOXIC AND HYPERTHERMIC SHOCKS UPON <i>TETRAHYMENA</i> RESPIRATION AND INTRACELLULAR ATP CONCENTRATION

Rooney, David; Eiler, John J.

doi:10.1083/jcb.41.1.145

Cited by 20 publications

(4 citation statements)

References 16 publications

(27 reference statements)

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“…The estimated K m for the ATP-dependent activity in our experiment is ∼25 μM, in the range of the K m for some known ATPase activities of chromatin remodeling complexes ( Cairns et al, 1996 ; Aalfs et al, 2001 ). Also, it is worth noting that Tetrahymena has a high intracellular ATP concentration (∼100–200 μM; Rooney and Eller, 1969 ), at which level the putative ATP-dependent chromatin remodeling processes can be fully active. It remains to be determined whether this process is carried out by known ATP-dependent complexes that modify core nucleosomes (for review see Aalfs and Kingston, 2000 ; Wu and Grunstein, 2000 ) or is unique and has distinct structural effects on chromatin.…”

Section: Discussionmentioning

confidence: 99%

Phosphorylation and an ATP-dependent process increase the dynamic exchange of H1 in chromatin

Dou

Bowen

Liu

et al. 2002

The Journal of Cell Biology

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In Tetrahymena cells, phosphorylation of linker histone H1 regulates transcription of specific genes. Phosphorylation acts by creating a localized negative charge patch and phenocopies the loss of H1 from chromatin, suggesting that it affects transcription by regulating the dissociation of H1 from chromatin. To test this hypothesis, we used FRAP of GFP-tagged H1 to analyze the effects of mutations that either eliminate or mimic phosphorylation on the binding of H1 to chromatin both in vivo and in vitro. We demonstrate that phosphorylation can increase the rate of dissociation of H1 from chromatin, providing a mechanism by which it can affect H1 function in vivo. We also demonstrate a previously undescribed ATP-dependent process that has a global effect on the dynamic binding of linker histone to chromatin.

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Section: Discussionmentioning

confidence: 99%

Phosphorylation and an ATP-dependent process increase the dynamic exchange of H1 in chromatin

Dou

Bowen

Liu

et al. 2002

The Journal of Cell Biology

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“…Heat shock of Tetrahymena spp. results in a change in mitochondrial morphology (30) as well as a decrease in the ATP concentration in the cell (14,46), indicating that mitochondrial structures and functions are directly affected by the stress. The role that hsp58 plays in the normal (i.e., nonstressed) functioning of the mitochondria is not known; however, as the major hsps, hsp73 and hsp8o, do not accumulate in mitochondria during stress, one possibility is that hsp58 plays a role in mitochondria during heat shock comparable to those played by hsp73 and hsp80 in the nucleus and cytosol.…”

Section: Discussionmentioning

confidence: 99%

A normal mitochondrial protein is selectively synthesized and accumulated during heat shock in Tetrahymena thermophila.

McMullin¹,

Hallberg²

1987

Mol. Cell. Biol.

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We have identified and purified a 58-kilodalton protein of Tetrahymena thermophila whose synthesis during heat shock parallels that of the major heat shock proteins. This protein, hsp58, was found in both non-heat-shocked as well as heat-shocked cells; however, its concentration in the cell increased approximately two-to threefold during heat shock. The majority of hsp58 in both non-heat-shocked and heat-shocked cells was found by both cell fractionation studies and immunocytochemical techniques to be mitochondrially associated. During heat shock, the additional hsp58 was found to selectively accumulate in mitochondria. Nondenatured hsp58 released from mitochondria of non-heat-shocked or heat-shocked cells sedimented in sucrose gradients as a 20S to 25S complex. We suggest that this protein may play a role in mitochondria analogous to the role the major heat shock proteins play in the nucleus and cytosol.Virtually every organism tested to date responds to hyperthermal stress by transiently inducing the synthesis and accumulation of a specific array of polypeptides commonly referred to as heat shock proteins (hsps) or stress proteins (summarized in references 4, 32, and 48). The major hsps of most organisms fall into size classes of approximately 80 to 90, 68 to 75, and 15 to 30 kilodaltons (kDa). Evolutionary conservation of DNA and amino acid sequences exhibited by the groups of major hsps, especially the hsp7O group (6, 10, 24-26, 32, 47), suggest that they must play fundamental metabolic roles in the cell. In many organisms, a variable array of minor hsps are also synthesized during heat shock (17,33,38,58,60). Collectively, these hsps are thought to protect the cell from the adverse effects of heat shock as well as other physiological stresses (summarized in references 4, 10, 32, and 48).While mutations in specific heat shock genes have been shown to affect the viability of the cells harboring those mutations (11,35,62), the exact functions of individual hsps are still not well understood. One approach to ascertaining the functions of individual hsps has been to determine the subcellular locations of those proteins. These studies have revealed that during heat shock certain hsps, such as some members of the 70-kDa group, and several of the small hsps tend to accumulate in the nucleus, while others, such as members of the 80-to 90-kDa group, remain cytosolic (3,17,35,51,56,59). Additionally, several of the small hsps appear to form cytoplasmic aggregates (2,40,49). In plants, several hsps were found to associate with chloroplasts (27, 57), ribosomes (31), and mitochondria (31,50). Although these studies clearly show differences in the localizations of the hsps, particular functions have not yet been ascribed to these proteins.In Tetrahymena thermophila, the heat shock response is typical and can be induced by shifting the organism from 30 to 41°C (16, 19, 20, 63). This induces the immediate and transient synthesis of the major hsps (73 kDa, 80 kDa, and 29 to 35 kDa) as well as several minor hsps (20,37). * Co...

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“…Cells can also be mechanically separated by physical methods such as flow cytometry, mitotic shake-off, and countercurrent centrifugal elutriation ( 18 ). Hypoxic shock and hyperthermic shock have been used to synchronize cells of the ciliate Tetrahymena pyriformis ( 20 ). Photosynthetic algal cells are typically exposed to alternative light/dark (L-D) cycles for synchronization ( 21 , 22 ).…”

Section: Introductionmentioning

confidence: 99%

Flagellar Synchronization Is a Simple Alternative to Cell Cycle Synchronization for Ciliary and Flagellar Studies

Dutta

Avasthi

2017

mSphere

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Cilia and flagella are highly conserved antenna-like organelles that found in nearly all mammalian cell types. They perform sensory and motile functions contributing to numerous physiological and developmental processes. Defects in their assembly and function are implicated in a wide range of human diseases ranging from retinal degeneration to cancer. Chlamydomonas reinhardtii is an algal model system for studying mammalian cilium formation and function. Here, we report a simple synchronization method that allows detection of small changes in ciliary length by minimizing variability in the population. We find that this method alters the key relationship between cell size and the amount of protein accumulated for flagellar growth. This provides a rapid alternative to traditional methods of cell synchronization for uncovering novel regulators of cilia.

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EFFECTS OF DIVISION-SYNCHRONIZING HYPOXIC AND HYPERTHERMIC SHOCKS UPON TETRAHYMENA RESPIRATION AND INTRACELLULAR ATP CONCENTRATION

Cited by 20 publications

References 16 publications

Phosphorylation and an ATP-dependent process increase the dynamic exchange of H1 in chromatin

Phosphorylation and an ATP-dependent process increase the dynamic exchange of H1 in chromatin

A normal mitochondrial protein is selectively synthesized and accumulated during heat shock in Tetrahymena thermophila.

Flagellar Synchronization Is a Simple Alternative to Cell Cycle Synchronization for Ciliary and Flagellar Studies

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