Histone H4 gene is transcribed in S phase but also late in G2
 phase in Physarum polycephalum

Wilhelm, M.L.; Toublan, B; Jalouzot, R.; Wilhelm, F.X.

doi:10.1002/j.1460-2075.1984.tb02190.x

Cited by 17 publications

(6 citation statements)

References 22 publications

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“…This does not preclude the possibility that a regulatory sequence that does not coincide with a replication origin exists near the human histone genes. We have recently monitored the level of histone H4 mRNA during the cell cycle of Physarum (21). Our data indicate that the level of mRNA is maximal at 30 min and then decreases.…”

Section: Discussionmentioning

confidence: 94%

“…The cross-hybridizes to the probe because it contains 0.2 kbp of noncoding sequence and is a HindIII/EcoRI fragment located 2 kbp downstream from the H41 gene. The copy number of H4 genes was determined for strain Tu 291 as previously described (21). The results (data not shown) suggest that, as in strain M3CVIII, there are only one or two copies of each H4 gene in the haploid genome of this strain.…”

mentioning

confidence: 89%

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Replication timing of the H4 histone genes in Physarum polycephalum.

Jalouzot¹,

Toublan²,

Wilhelm³

et al. 1985

Proc. Natl. Acad. Sci. U.S.A.

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The time of replication of the two H4 histone genes (H41 and H42) was determined during the naturally synchronous mitotic cycle of Physarum polycephalum. 5-Bromo-2'-deoxyuridine labeling and density gradient centrifugation was used to isolate newly synthesized DNA from defined periods of S phase. The DNA was analyzed by Southern hybridization with a cloned probe containing one of the H4 histone genes ofPhysarum. The results indicate that the two H4 histone genes are replicated in the first 30 min of S phase but not exactly at the same time. H41 is replicated during the frt 10 min of S phase, when only 15% of the genome is duplicated, whereas H42 replicates between 20 and 30 min after the onset of S phase. The possible relationship between the periodic expression of the genes and the timing of their replication is discussed.In eukaryotes, as in prokaryotes, the replication of specific DNA sequences follows a distinct temporal order (1, 2). DNA replicated in one period of the S phase is replicated in the same temporal interval of the next S phase. In early experiments autoradiography and cytology was used to demonstrate that the chronological order of replication of specific DNA segments is invariant from one cell generation to the next (3).In mammalian cells, multiple copy sequences have been found to replicate mainly late in S phase, whereas families of middle-repetitive sequences replicate either early or late (for references see ref. 4). "Housekeeping" or active tissuespecific genes are generally replicated early. Furst et al. (5) and Epner et al. (6) have, for example, demonstrated that the replication of globin genes in mouse erythroleukemia cells is predominantly restricted to the first third of S phase. In the same manner, studies by Braunstein et al. (7) have shown that the replication of the immunoglobulin heavy chain constant region gene segments CQ, Cy, and C, is restricted to the first half of S and follows the linear order in which they are arranged in the genome. Recently Calza et al. (8) have presented evidence that certain low-copy-number genes can be replicated late and have suggested that the gene's position in the chromosome is important in determining the time during S at which it is replicated. All the results presented on the timing of gene replication support the idea that earlyreplicating genes are capable of expression, and Goldman et al. (4) suggest that the switching of specific genes from an early to a late replication region reflects the commitment of that gene to quiescence.The sustained synchrony over several successive nuclear division cycles in the syncytial plasmodia phase of the myxomycete Physarum polycephalum was exploited by Braun et al. (9) to demonstrate that chromosomal DNA is replicated in a defined temporal sequence. In addition, Fouquet and Sauer (10) have shown that repetitive DNA of Physarum is synthesized during late S phase. At the level of specific genes, Pierron et al. (11) have recently found that the four actin loci are replicated in an invariant tempo...

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Section: Discussionmentioning

confidence: 94%

mentioning

confidence: 89%

Replication timing of the H4 histone genes in Physarum polycephalum.

Jalouzot¹,

Toublan²,

Wilhelm³

et al. 1985

Proc. Natl. Acad. Sci. U.S.A.

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“…It has been shown, that histone synthesis is tightly coupled to DNA replication during the synchronous Physarum cell cycle (13,14). Interestingly the histone H4 gene of Physarum is transcribed not only during S-phase but also during late G2-period without concomitant translation of the message (15). Posttranslational acetylation of histone H4 (16), phosphorylation of Hi (17) and ubiquitination of H2A and H2B (18) undergo distinct cell cycle dependent fluctuations in Physarum.…”

Section: Introductionmentioning

confidence: 99%

Biosynthesis and posttranslational acetylation of histones during spherulation ofPhysarum polycephalum

Loidl¹,

Gröbner²

1986

Nucl Acids Res

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Plasmodia of Physarum polycephalum can be induced to differentiate into dormant spherules: DNA-, RNA- and protein-synthesis cease during this process. Analysis of the histone H4 acetylation during spherulation revealed no significant changes of the relative acetate content and percentage of acetylated H4 subspecies. This result does not support a close correlation of histone acetylation and transcriptional activity. Posttranslational incorporation of 3H-acetate into core histones decreased rapidly after start of spherulation. However, acetate incorporation increased significantly at a late stage of spherulation (30 h). To elucidate the role of this elevated acetate incorporation we followed histone synthesis during spherulation. Histone synthesis decreased upon induction of differentiation and stopped after 12 h. After 38 h of spherulation histone synthesis again occurred in the absence of DNA synthesis. The peak of acetate incorporation into core histones clearly preceded this late histone synthesis, indicating acetylation of preexisting histones. We suggest, that this acetate incorporation is part of the mechanism, by which preexisting histones are replaced by newly synthesized histones. Pulse treatment with actinomycin D or cycloheximide during spherulation suggested, that the observed histone synthesis is essential for the germination of spherules. Obviously, new histones have to be synthesized for the coordinate course of the differentiation program.

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“…However, as the commercial antibodies recognized conserved modifications of histones, it was required to verify that the Physarum histones present a high homology. The Physarum histone H4, the cloning the gene revealed that the protein is highly conserved as only two amino-acid residues are different from the human protein (Wilhelm et al, 1984). For the histone H3, we have identified two genes that encoded for two H3 proteins that exhibited slight differences in the globular domain, but the tail domain is identical to the human histone.…”

Section: Natural Synchrony Of Physarum Nuclei Throughout the Cell Cyclementioning

confidence: 96%

Histone Tail Modifications of H3 and H4 during the Physarum polycephalum Cell Cycle

Yoshihisa¹

2012

OnLine Journal of Biological Sciences

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Problem statement: Histone modifications are required for chromatin activities and are believed to form an epigenetic code. However, the inheritance of the histone post-translational modifications remains unclear. Approach and Results: The aim of this study was to evaluate the histone modifications throughout the cell cycle and to determine whether the histone marks are transferred to daughter cells. Using the naturally synchronous model system Physarum polycephalum and Western blotting analyses, we showed that the histone modifications are not exclusive of the cell cycle stage. Importantly, we also demonstrated that during mitosis, a substantial fraction of the acetylation and the methylation marks of the histone H3 and H4 is removed. Conclusion: The results illustrate that a part of the histone modifications are displaced during mitosis and thus failed to exhibit an inheritance to daughter cells as proposed for the epigenetic marks.

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Histone H4 gene is transcribed in S phase but also late in G₂ phase in Physarum polycephalum

Cited by 17 publications

References 22 publications

Replication timing of the H4 histone genes in Physarum polycephalum.

Replication timing of the H4 histone genes in Physarum polycephalum.

Biosynthesis and posttranslational acetylation of histones during spherulation ofPhysarum polycephalum

Histone Tail Modifications of H3 and H4 during the <i>Physarum polycephalum</i> Cell Cycle

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Histone H4 gene is transcribed in S phase but also late in G2 phase in Physarum polycephalum

Cited by 17 publications

References 22 publications

Replication timing of the H4 histone genes in Physarum polycephalum.

Replication timing of the H4 histone genes in Physarum polycephalum.

Biosynthesis and posttranslational acetylation of histones during spherulation ofPhysarum polycephalum

Histone Tail Modifications of H3 and H4 during the <i>Physarum polycephalum</i> Cell Cycle

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Histone H4 gene is transcribed in S phase but also late in G₂ phase in Physarum polycephalum