Pair formation in <i>Tetrahymena pyriformis</i>, an inducible developmental system

Bruns, Peter J.; Brussard, Trudy B.

doi:10.1002/jez.1401880309

Cited by 206 publications

(94 citation statements)

References 18 publications

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“…7 C, lanes 1 and 2); and (b) a hyperphosphorylation occurs when starved cells are subjeered to stress such as heat shock (Glover et al, 1981). To further demonstrate that the synthesis of LG-2 is not simply a stress-induced phenomenon and is indeed conjugation specific, starved cells have been placed on a fast shaker under conditions that block costimulation, a prerequisite for conjugation (Bruns and Brussard, 1974). Ceils treated in this manner and labeled with [3H]lysine between 2 and 3 h do not hyperphosphorylate H1 or synthesize LG-2 (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Tetrahymena contain two distinct and unusual high mobility group (HMG)-like proteins.

Schulman¹,

Cook²,

Richman³

et al. 1987

The Journal of Cell Biology

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Section: Discussionmentioning

confidence: 99%

Tetrahymena contain two distinct and unusual high mobility group (HMG)-like proteins.

Schulman¹,

Cook²,

Richman³

et al. 1987

The Journal of Cell Biology

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“…Cells were grown in super proteose peptone medium (1% proteose peptone, 0.1% yeast extract, 0.2% glucose, 90 M EDTA ferric sodium salt) at 30°C (31). For conjugation, midlogarithmic phase growing cultures of different mating types were washed, starved (16 -24 h at 30°C), and mated in 10 mM Tris-HCl (pH 7.5) (32).…”

Section: Methodsmentioning

confidence: 99%

Histone H2B Ubiquitylation Is Not Required for Histone H3 Methylation at Lysine 4 in Tetrahymena

Wang

Cui²,

Gorovsky

2009

Journal of Biological Chemistry

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Ubiquitylation of histone H2B and/or a component of the system that ubiquitylates H2B is required for methylation of histone H3 at lysine 4 (H3K4) in yeasts and probably in humans. In this study, the single ubiquitylation site was mapped to conserved lysine 115 of the C-terminal region of histone H2B in the single-cell model organism Tetrahymena thermophila. In strains lacking H2B ubiquitylation, H3K4 methylation was not detectably affected. As in other organisms, the E2 ubiquitinconjugating enzyme Ubc2 and the E3 ubiquitin ligase Bre1 were required for H2B ubiquitylation. However, neither enzyme was required for H3K4 methylation. These studies argue that, in T. thermophila, the histone ubiquitylation mechanism is not required for H3K4 methylation, demonstrating that different organisms can speak different languages in the "cross-talk" among post-translational modifications on different histones.In the nuclei of eukaryotic cells, DNA is highly compacted into chromatin, a nucleoprotein complex, whose major protein components are the histones. The basic unit of chromatin is the nucleosome core in which 146 base pairs of double-stranded DNA are wrapped in ϳ1.75 left-handed superhelical turns around an octamer containing two molecules of each of the four conserved core histones H2A, H2B, H3, and H4 (1, 2). A fifth, less conserved linker histone H1, associates with a variable length of linker DNA between nucleosome cores. Site-specific histone post-translational modifications, such as acetylation, methylation, phosphorylation, and ubiquitylation, are correlated with diverse chromatin functions, including DNA replication, DNA repair, chromatin assembly, gene transcription, and other chromatin-based processes (3, 4). It has been suggested that at least some distinct histone modifications act sequentially or in combination to form what has been variously referred to as a histone, epigenetic, or nucleosome "code" that is read by other proteins or protein complexes to alter chromatin structure and regulate distinct downstream events (5, 6). Deciphering this code, which is likely to have complex redundant, combinatorial, and multivalent features, is essential for understanding the in vivo function of the diverse post-translational modifications on histones.Ubiquitin is a 76-amino acid globular protein that is conserved in eukaryotes. Unlike proteins that are targeted by polyubiquitylation to the proteosome for degradation, histones are reversibly modified by covalent attachment of one ubiquitin or a short ubiquitin chain. The bulk of histone ubiquitylation occurs on chromatin by the addition of a single ubiquitin molecule via an isopeptide linkage to a specific lysine residue in the C-terminal tail of histones H2A and H2B (7,8). To a lesser extent, histones H1 (9), H3, and H4 (10, 11) also can be ubiquitylated in vivo. Ubiquitylation on different histones has distinct functions (12).A number of recent studies have focused on ubiquitylation of H2B. In the budding yeast Saccharomyces cerevisiae, H2B is monoubiquitylated at l...

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“…The rate of flow was found to be optimal with respect to the yield of cells at about 2 ml. min-L Finally, we tested the ability of the column to eliminate non-conjugants at the later stages of conjugation by using a mating mixture of cells containing dominant mutations in the micronucleus but recessive markers in the macronucleus, allowing a simple test for the development of new macronuclei (2). Six hours after mixing the two strains, ovalbumin treated ferrite (10 mg. ml -I) was added to the mating mixture, and P. J. BRUNS et ai.…”

Section: Resultsmentioning

confidence: 99%