Macromolecule synthesis and the influence of actinomycin on early development

Gross, Paul R.; Cousineau, Gilles H.

doi:10.1016/0014-4827(64)90002-3

Cited by 288 publications

(55 citation statements)

References 22 publications

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“…Fig. 4 shows that the CS to a transition can also be triggered by artificial activation with pH 9.0 ammonia-seawater (26). The pattern of proteins made is very similar to that seen after fertilization.…”

Section: The Pattern Of Protein Synthesis Changes After Fertilizationmentioning

confidence: 57%

“…Eggs were then pelleted by hand centrifugalion and fertilized in MPFSW. Fertilized eggs were washed to remove excess sperm, washed twice in 25 t~g/ml actinomycin D in MPFSW, and cultured in this solution in the dark to the blastula stage (5,26,27), Nuclei from blastulae grown in actinomycin were isolated by Dounce homogenization in 0.075 M NaC1, 25 mM Tris, I mM EDTA pH 7.6 solution containing 0.01% Triton X-100 as described in Poccia et al (24).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Translational regulation of histone synthesis in the sea urchin strongylocentrotus purpuratus.

Herlands¹,

Allfrey²,

Poccia³

1982

The Journal of Cell Biology

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The pattern and schedule of histone synthesis in unfertilized eggs and early embryos of the sea urchin Strongylocentrotus purpuratus were studied using two-dimensional gel electrophoresis. After fertilization there is an abrupt change in the pattern of histone variant synthesis. Although both cleavage-stage-and c~-histone mRNA are stored in sea urchin eggs, unfertilized eggs synthesize only cleavage-stage (CS) variants. However, after fertilization, both CS and c~ messages are translated. Since histone mRNA isolated from unfertilized eggs can be translated in vitro, the synthesis of ~ histone subtypes appears to be under translational control. Although the synthesis of ~ subtypes is shown here to occur before the second S phase after fertilization, little or no c~ histone is incorporated into chromatin at this time. Thus, early chromatin is composed predominantly of CS variants probably recruited for the most part from the large pool of CS histones stored in the unfertilized egg.During sea urchin development, histone variants of the HI, H2A, and H2B classes appear sequentially in the chromatin (1-6). Variants of each class are coded by different members of the histone multigene family and differ from each other in primary amino acid sequence (5, 7-9). Characteristic sets of histones are made and assembled into chromatin at each of several developmental stages. Cleavage-stage (CS) histones are the first to appear (4). They are presumably made during oogenesis and are stored in the unfertilized egg in large quantities (at least several hundred haploid DNA equivalents [10, 11]). The CS variants participate in an extensive remodeling of the sperm chromatin after fertilization, which results in a reduction in the nucleosome repeat length (12). Almost immediately after fertilization, the sperm H1 variant is replaced by CS HI. Concomitant with DNA synthesis, substantial amounts of CS H2A and CS H2B accumulate in the chromatin. These protein transitions can take place in the absence of protein synthesis. Later in development the ct variants appear, and, by the morula stage, chromatin is composed predominantly of nucleosomes that contain a histones (1, 4). Synthesis of late histones (designated /3, -/, and 8) is initiated at the mesenchyme blastula stage (1, 4). When sea urchin maternal mRNA is translated in vitro, both a (6, 8, 13) and CS histones (8) are made. Because both a and CS histone mRNAs are stored in the sea urchin egg, it is surprising that mature eggs contain only CS proteins. There is no detectable storage of a histones (11). These observations suggest that the synthesis of histone subtypes may be under translational control. On the basis of the observation that newly synthesized a variants, incorporated into chromatin, are first detected at about the third S phase after fertilization, others have suggested a qualitative translational control for histone variant synthesis (4, 6).Fertilization of the sea urchin egg stimulates the rate of protein synthesis -15-fold by 2 h postfertilization (14). Thi...

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Section: The Pattern Of Protein Synthesis Changes After Fertilizationmentioning

confidence: 57%

Section: Methodsmentioning

confidence: 99%

Translational regulation of histone synthesis in the sea urchin strongylocentrotus purpuratus.

Herlands¹,

Allfrey²,

Poccia³

1982

The Journal of Cell Biology

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“…RNA synthesis is not required for cleavage (unpublished data for Xenopus; see ref. 29 for Arbacia) and, in fact, very little RNA synthesis takes place (5). Thus, in the early blastula stages of amphibian development we have an abbreviated cell cycle consisting of only DNA synthesis and mitosis and having few biosynthetic requirements.…”

Section: Resultsmentioning

confidence: 99%

A cytoplasmic clock with the same period as the division cycle in Xenopus eggs.

Hara¹,

Tydeman²,

Kirschner³

1980

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

302

165

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In most species the cell cycle is arrested in the unfertilized egg. After fertilization the cell cycle is reestablished and a rapid series of cleavages ensues. Preceding the first cleavage in Xenopus the egg undergoes a contraction of its cortex, called the "surface contraction wave," which can be visualized by time-lapse cinematography. This wave of contraction is propagated in a circular manner from the animal pole to the equator. We have found that eggs prevented from cleaving by treatment with antimitotic drugs undergo a sequence of periodic surface contraction waves timed with the cleavage cycle in untreated eggs. In addition, artificially activated eggs, which fail to cleave presumably for lack of a functioning centriole, undergo the same periodic contractions. No nuclear material is required for the periodic waves because a separated egg fragment, produced by constricting a fertilized egg, still undergoes contraction waves with the same period as the cleaving nucleated fragment. These results demonstrate that some expression of the cell cycle persists in the absence of any nuclear material or centrioles, suggesting to us that a biological clock exists in the cytoplasm or cortex of vertebrate eggs, which may be involved in timing the cell cycle.In most species, the cell cycle is arrested in the unfertilized egg and is then reinstated by fertilization. In amphibians, after fertilization there is a somewhat long period leading up to the first cleavage and then cells in the animal, equatorial, and vegetal regions in sequence proceed through a rapid series of 10 or 11 metachronous cleavages until the midblastula stage is reached. During the metachronous cleavage period, the cells within each region divide synchronously. Thereafter, the cell cycle variably lengthens and cleavage becomes totally asynchronous (1-3). Thus, in amphibian development, the cell cycle is acquired in steps after fertilization, beginning with a short rudimentary cycle containing only M and S phases and characterized by little if any transcriptional activity and followed by a longer cell cycle having G1 and G2 phases and active RNA synthesis (4-6). Because the high degree of synchrony at the early stages is preserved when the individual blastomeres are dissociated and separated (ref. 2 and unpublished data), the machinery for timing accurately the alternate waves of DNA synthesis and mitosis must be partitioned to each of the daughter cells. An understanding of the mechanism of timing of the simple cell cycle in the early cleavage period may be useful for understanding the overall control of the cell cycle in somatic cells.Although many cell types have been used for studies of the cell cycle, the amphibian egg offers some special advantages. Its large size permits enucleation and nuclear transplantation, allowing a clear-cut distinction between the contributions of the nucleus and the cytoplasm. In general, the lack of activity of the nucleus in the early cleavage period makes the egg a good system for studying the autonomy of the...

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“…In spite of these pioneer's works an unresolved question concerning the hatching enzyme synthesis has remained under discussion : When does this enzyme protein transcribe and synthesize through embryogenesis ? In order to resolve this question, a number of experiments have been reported on developing sea urchin embryos, using actinomycin D which has been known as an antibiotic inhibitor of m-RNA synthesis (Yasumasu 1963;Gross et al 1964) . It should be noted, however, that the experiments of these antibiotic which induced effects were limited almost on the sea urchin embryos.…”

mentioning

confidence: 99%