Activity of a DNA topoisomerase (nicking-closing enzyme) during sea urchin development and the cell cycle

Poccia, Dominic; Levine, D.; Wang, J.C.

doi:10.1016/0012-1606(78)90078-7

Cited by 38 publications

(11 citation statements)

References 25 publications

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“…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%

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: 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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“…Eukaryotic organisms or cells from which type I topoisomerases have been isolated include: lower eukaryotes like yeast (DURNFORD and CHAMPOUX 1978;BADARACCO et al 1983; or Ustilago maydis, another fungus (ROWE et al 1981); the protozoon Trypanosoma cruzi ; tissue culture cells of mouse and human origin (KELLER 1975a;VOSBERG and VINO-GRAD 1976;TANG 1978;Lru and MILLER 1981;DURBAN et al 1983;ISlllI et al 1983); rat and bovine liver (CHAMPOUX and MCCONAUGHY 1976;KOWALSKI 1980); calf thymus (PULLEYBLANK and MORGAN 1975b;PRELL and VOSBERG 1980;SCHMITT et al 1984); avian erythrocytes (CAMERINI-OTERO and FELSENFELD 1977;BINA-STEIN et al 1976;PULLEYBLANK and ELLISON 1982;TRICOLI and KOWALSKI 1983;TRASK and MULLER 1983); D. melanogaster eggs and embryos (BAASE and WANG 1974;HSIEH and BRUTLAG 1980;JAVAHERIAN et al 1982); X. laevis (LASKEY et al 1977;MATTOCIA et al 1976;GANDINI-ATTARDI et al 1981); salmon testis (ESKIN and MORGAN 1978); and sea urchins (POCCIA et al 1978). In addition, two reports exist on similar enzymes in higher plants, wheat germ (DYNAN et al 1981), and cauliflower (FUKATA and FUKA-SAWA 1982).…”

Section: Eukaryotic Type I Topoisomerasesmentioning

confidence: 99%

DNA Topoisomerases: Enzymes That Control DNA Conformation

Vosberg

1985

Current Topics in Microbiology and Immunology

233

166

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“…Gametes were obtained by intracoelomic injection of0.5 M KCl. Monospermic cultures were raised as described (25). Polyspermic eggs were prepared and cultured according to Poccia et al (26).…”

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confidence: 99%

“…Polyspermic eggs were prepared and cultured according to Poccia et al (26). Nuclei were prepared by an aqueous ethanol/Triton X-100 procedure as described for embryonic nuclei (25), pronuclei from polyspermic eggs (26), and sperm nuclei (25). Repeat distances were equivalent for sperm nuclei made by the above procedure or a standard aqueous sucrose technique (27 in sperm are rapidly decreased in embryo chromatins (Fig.…”

mentioning

confidence: 99%

“…The average degree of polyspermy A (number of male pronuclei per egg) was determined for each culture used because the timing of the first cell cycle is ii dependent (26). The experiments were arbitrarily divided into low, medium, and high degrees of polyspermy in ranges that show significantly different lengths ofcell cycle parameters such as duration of S phase or onset time of the first mitotic chromosome condensation (25). In all cases, S phase begins at =30 min after fertilization.…”

mentioning

confidence: 99%

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Alterations in chromatin structure during early sea urchin embryogenesis.

Savić¹,

Richman²,

Williamson³

et al. 1981

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

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Sea urchin sperm before fertilization possess the longest nucleosome repeat length yet determined for any chromatin. By the time the fertilized egg gives rise to a blastula or gastrula embryo, the chromatin has a considerably shorter repeat length and, in addition, a sequence of different histone variants of HI, H2A, and H2B has appeared. We have investigated the relationship between these variations in histone composition and concomitant alterations in chromatin structure during the earliest stages of embryogenesis in two species of sea urchin. In contrast to the long repeat distance in sperm, chromatin loaded with cleavage-stage histones has a much smaller repeat. Later stages containing predominantly a histones display an intermediate spacing.More detailed analysis of the events in the first cell cycle was carried out with polyspermically fertilized eggs. During the first 30 min after fertilization, in which sperm-specific HI is completely replaced by cleavage-stage HI, the male pronuclear repeat remains unchanged. The decrease toward the repeat length ofcleavage stages begins at about the time of DNA synthesis. Higher degrees of polyspermy extend the length of the cell cycle, including the duration of S phase and the length of time to reach the first chromosome condensation. At these higher degrees of polyspermy, the decrease in repeat length is also slowed. We conclude that the adjustment of the arrangement of nucleosomes in embryonic chromatin from that found in sperm can occur within the first cell cycle and that its timing is cell-cycle dependent. The adjustment is separable from a corresponding change in HI composition. The structure ofeukaryote chromatin is based on repeating subunits, or nucleosomes, linked by structurally distinct regions of spacer DNA. Core nucleosomes invariably contain 146 base pairs (bp) of nuclease-resistant DNA organized by a protein octamer consisting of two each ofhistones H2A, H2B, H3, and H4 (1-4).Another class of histones, Hi, is not contained in the core structure and is probably associated with the spacer DNA linking the cores (5-7). The DNA linking the cores is not invariant; its average length varies with species, cell type, and developmental stage (8)(9)(10)(11)(12)(13)(14). The functional significance of this variability is unknown, although transcriptional activity, cell proliferation rate, and chromosome condensation are among the functions that could be affected by variations in spacer length (3,8). Also unclear is the underlying structural basis ofthis variability; different spacer lengths could arise from differences in Hi histones, core histones (especially H2A and H2B variants), posttranslational modifications, or nonhistone proteins (3). Of these, the potential role of the very lysine-rich (Hl-like) histones has received the most attention; a number ofauthors have described correlations between alterations in nucleosome spacing and changes in the lysine-rich histone composition of the chromatin (10,11,15,16).One potentially fruitful system in which t...

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Activity of a DNA topoisomerase (nicking-closing enzyme) during sea urchin development and the cell cycle

Cited by 38 publications

References 25 publications

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

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

DNA Topoisomerases: Enzymes That Control DNA Conformation

Alterations in chromatin structure during early sea urchin embryogenesis.

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