Chromatin remodeling during sea urchin early development: molecular determinants for pronuclei formation and transcriptional activation

Imschenetzky, María; Puchi, Marcia; Morín, Violeta; Medina, Ricardo; Montecino, Martín

doi:10.1016/j.gene.2003.08.024

Cited by 18 publications

(26 citation statements)

References 129 publications

(141 reference statements)

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“…In most animals, the nucleus of the sperm is different in structure and appearance from nuclei of somatic cells or developing embryos. The chromatin in mature sperm nuclei is highly condensed, often as a consequence of association with sperm-specific packaging proteins such as protamines (reviewed in Poccia and Collas, 1996; Jayaramaiah Raja and Renkawitz-Pohl, 2005) or sperm-specific histones (reviewed in Imschenetzky et al, 2003). This tight packaging has been postulated to streamline sperm for motility, protect sperm DNA from physical and chemical damage, and reset somatic histone epigenetic modifications (reviewed in Poccia and Collas, 1996;Rousseaux et al, 2005).…”

Section: Conversion Of the Sperm Nucleus Into A Male Pronucleusmentioning

confidence: 99%

“…The sperm nuclear envelope, if present, is removed and sperm-specific protamines or histones are replaced by histone variants from maternal stores (reviewed in Collas, 2000;Imschenetzky et al, 2003). The replacement of sperm-specific proteins with maternal histones is generally correlated with some decondensation of the sperm nucleus.…”

Section: Conversion Of the Sperm Nucleus Into A Male Pronucleusmentioning

confidence: 99%

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Transitioning from egg to embryo: Triggers and mechanisms of egg activation

Horner

Wolfner

2008

Developmental Dynamics

183

177

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The transition from mature oocyte to developing embryo requires a coordinated series of events, collectively known as egg activation. Egg activation includes changes to egg coverings to prevent polyspermy, release of oocyte meiotic arrest, generation of haploid female and male pronuclei, changes in maternal mRNAs and protein populations, and cytoskeletal rearrangements. In many animals, egg activation is triggered by fertilization, which increases intracellular calcium within the oocyte and thereby regulates molecular events of egg activation. In other animals, fertilization-independent external signals, including mechanical stimulation of eggs and/or changes in ionic milieu, trigger activation. Recent studies have clarified the upstream portion of pathways leading to eggshell changes and cell cycle resumption and have identified activation-induced changes in maternal mRNA and protein profiles that can identify molecular players in the downstream events of egg activation. We review signals that trigger activation and how they link to subsequent molecular events of egg activation. Developmental Dynamics 237:527-544, 2008.

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Section: Conversion Of the Sperm Nucleus Into A Male Pronucleusmentioning

confidence: 99%

Section: Conversion Of the Sperm Nucleus Into A Male Pronucleusmentioning

confidence: 99%

Transitioning from egg to embryo: Triggers and mechanisms of egg activation

Horner

Wolfner

2008

Developmental Dynamics

183

177

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“…In sea urchins, the complete set of sperm histones (SpH) is removed from chromatin and replaced by maternally inherited CS histone variants (reviewed by Imschenetzky et al [2003]). We had also shown that the SpH released from male chromatin are degraded by a nuclear cysteine protease (SpHprotease) that catalyzes the SpH proteolysis, leaving the CS histone variants unaffected [Imschenetzky et al, 1997].…”

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confidence: 99%

Sperm nucleosomes disassembly is a requirement for histones proteolysis during male pronucleus formation

Iribarren

Morín

Puchi

et al. 2007

J of Cellular Biochemistry

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We had previously reported that a cysteine-protease catalyzes the sperm histones (SpH) degradation associated to male chromatin remodeling in sea urchins. We found that this protease selectively degraded the SpH leaving maternal cleavage stage (CS) histone variants unaffected, therefore we named it SpH-protease. It is yet unknown if the SpH-protease catalyzes the SpH degradation while these histones are organized as nucleosomes or if alternatively these histones should be released from DNA before their proteolysis. To investigate this issue we had performed an in vitro assay in which polynucleosomes were exposed to the active purified protease. As shown in this report, we found that sperm histones organized as nucleosomes remains unaffected after their incubation with the protease. In contrast the SpH unbound and free from DNA were readily degraded. Interestingly, we also found that free DNA inhibits SpH proteolysis in a dose-dependent manner, further strengthening the requirement of SpH release from DNA before in order to be degraded by the SpH-protease. In this context, we have also investigated the presence of a sperm-nucleosome disassembly activity (SNDA) after fertilization. We found a SNDA associated to the nuclear extracts from zygotes that were harvested during the time of male chromatin remodeling. This SNDA was undetectable in the nuclear extracts from unfertilized eggs and in zygotes harvested after the fusion of both pronuclei. We postulate that this SNDA is responsible for the SpH release from DNA which is required for their degradation by the cysteine-protease associated to male chromatin remodeling after fertilization.

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“…98: 335-342, 2006. Key words: protease; fertilization; cell cycle; sea urchins; embryogenesis During male pronucleus formation in sea urchins, the complete set of sperm histones (SpH) is removed from sperm chromatin and replaced by maternally inherited CS histone variants [reviewed by Imschenetzky et al, 2003]. The loss of sperm histones was found to be a step-wise process; initially the H3-H4 tetramer disappears and finally at the time of the fusion of male and female pronucleus SpH1 and the SpH2A-SpH2B dimers are lost [Imschenetzky et al, 1991].…”

mentioning

confidence: 99%

Microinjection of an antibody against the cysteine‐protease involved in male chromatin remodeling blocks the development of sea urchin embryos at the initial cell cycle

Puchi

Quiñones

Concha

et al. 2006

J of Cellular Biochemistry

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We reported recently that the inhibition of cysteine-proteases with E-64-d disturbs DNA replication and prevents mitosis of the early sea urchin embryo. Since E-64-d is a rather general inhibitor of thiol-proteases, to specifically target the cysteine-protease previously identified in our laboratory as the enzyme involved in male chromatin remodeling after fertilization, we injected antibodies against the N-terminal sequence of this protease that were able to inhibit the activity of this enzyme in vitro. We found that injection of these antibodies disrupts the initial zygotic cell cycle. As shown in this report in injected zygotes a severe inhibition of DNA replication was observed, the mitotic spindle was not correctly bipolarized the embryonic development was aborted at the initial cleavage division. Consequently, the injection of these antibodies mimics perfectly the effects previously described for E-64-d, indicating that the effects of this inhibitor rely mainly on the inhibition of the cysteine-protease involved in male chromatin remodeling after fertilization. These results further support the crucial role of this protease in early embryonic development.

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Chromatin remodeling during sea urchin early development: molecular determinants for pronuclei formation and transcriptional activation

Cited by 18 publications

References 129 publications

Transitioning from egg to embryo: Triggers and mechanisms of egg activation

Transitioning from egg to embryo: Triggers and mechanisms of egg activation

Sperm nucleosomes disassembly is a requirement for histones proteolysis during male pronucleus formation

Microinjection of an antibody against the cysteine‐protease involved in male chromatin remodeling blocks the development of sea urchin embryos at the initial cell cycle

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