Evolutionary changes in CpG and methylation levels in the genome of vertebrates

Jabbari, Kamel; Cacciò, Simone M.; Barros, J.-P. Pais de; Desgrès, J; Bernardi, Giorgio

doi:10.1016/s0378-1119(97)00475-7

Cited by 102 publications

(112 citation statements)

References 56 publications

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“…1). Because the sperm genome is highly methylated in all of these species (25), this finding shows that genome-wide demethylation of the paternal genome is conserved in eutherian mammals. We next examined bovine cleavage stage embryos in comparison with the mouse (Fig.…”

Section: Conservation Of Methylationmentioning

confidence: 82%

Conservation of methylation reprogramming in mammalian development: Aberrant reprogramming in cloned embryos

Dean

Santos

Stojković

et al. 2001

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

881

651

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Mouse embryos undergo genome-wide methylation reprogramming by demethylation in early preimplantation development, followed by remethylation thereafter. Here we show that genomewide reprogramming is conserved in several mammalian species and ask whether it also occurs in embryos cloned with the use of highly methylated somatic donor nuclei. Normal bovine, rat, and pig zygotes showed a demethylated paternal genome, suggesting active demethylation. In bovine embryos methylation was further reduced during cleavage up to the eight-cell stage, and this reduction in methylation was followed by de novo methylation by the 16-cell stage. In cloned one-cell embryos there was a reduction in methylation consistent with active demethylation, but no further demethylation occurred subsequently. Instead, de novo methylation and nuclear reorganization of methylation patterns resembling those of differentiated cells occurred precociously in many cloned embryos. Cloned, but not normal, morulae had highly methylated nuclei in all blastomeres that resembled those of the fibroblast donor cells. Our study shows that epigenetic reprogramming occurs aberrantly in most cloned embryos; incomplete reprogramming may contribute to the low efficiency of cloning.

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Section: Conservation Of Methylationmentioning

confidence: 82%

Conservation of methylation reprogramming in mammalian development: Aberrant reprogramming in cloned embryos

Dean

Santos

Stojković

et al. 2001

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

881

651

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“…One explanation might reside in genomic composition or in the methylation levels of mature spermatozoa. Using an HPLC assay, Jabbari et al (29) demonstrated that sheep, cow, and pig have Ϸ10% lower levels of 5mC in sperm than human and mouse, despite little difference in the frequency of CpG in the respective genomes. Thus, the sheep genome may simply not require such an extensive loss of methylation to initiate reprogramming in the early embryo (12).…”

Section: Discussionmentioning

confidence: 99%

The effect of interspecific oocytes on demethylation of sperm DNA

Beaujean

Taylor

McGarry

et al. 2004

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

114

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In contrast to mice, in sheep no genome-wide demethylation of the paternal genome occurs within the first postfertilization cell cycle. This difference could be due either to an absence of a sheep demethylase activity that is present in mouse ooplasm or to an increased protection of methylated cytosine residues in sheep sperm. Here, we use interspecies intracytoplasmic sperm injection to demonstrate that sheep sperm DNA can be demethylated in mouse oocytes. Surprisingly, mouse sperm can also be demethylated to a limited extent in sheep oocytes. Our results suggest that the murine demethylation process is facilitated either by a spermderived factor or by male pronuclear chromatin composition.M ethylation of the DNA cytosine residues in CpG dinucleotides is part of the complex epigenetic mechanism that has evolved to silence genomic sequences where their transcription either is not required for development or may be detrimental to genomic stability (reviewed in refs. 1-3). DNA methylation also plays an important role in allele-specific repression at imprinted gene loci, regulating such processes as fetal growth and development as well as X inactivation (reviewed in refs. 4-6). Whereas the genome-wide methylation patterns and levels of differentiated somatic lineages remain largely constant, very dynamic changes have been reported to occur in the preimplantation embryo in association with the formation of pluripotent embryonic nuclei.After fertilization, the sperm and egg genomes are remodeled into pronuclei, which appose within the oocyte cytoplasm before the first embryonic mitosis. However, the highly condensed sperm chromatin requires extensive nuclear remodeling and protamine-histone exchange, unlike nucleosomal maternal chromatin. By using an antibody against 5-methylcytosine (5mC), the presumptive male pronucleus of mouse, rat, pig, human, and, to a lesser extent, cow embryos have been shown to actively demethylate before syngamy, whereas the female pronucleus retains genome-wide methylation (7-12). In contrast, active demethylation of the paternal genome is not observed in early sheep or rabbit embryos (with an intermediate state in the cow) (12), which suggests that it is not an obligate requirement for mammalian development. The discovery that the dramatic changes in DNA methylation associated with early formative events in the mouse embryo are not conserved in the sheep allows a unique opportunity to investigate the regulatory mechanisms involved. Mouse ooplasm can fully demethylate multiple male pronuclei in polyspermic embryos, which raises the question of whether the demethylating activity resides in the fertilized oocyte or is intimately associated with the sperm (10). We have now used interspecies intracytoplasmic sperm injection (ICSI) to mimic the events of normal fertilization and investigate whether species differences in the oocyte environment or sperm composition determines the extent of male pronuclear demethylation. Materials and MethodsAll animal procedures were under strict accordance with...

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“…Известно, что распределение нуклеотидов в геномной ДНК отличается от случайного. Содержание комплементарных нуклеотидов G и С (G/C-пар) в геноме крыс составляет 43,9% [21,22]. Содержание G/C-пар в исследуемой ДНК оказалось повышенным и составило в среднем 48%.…”

Section: рисунок2unclassified

“…Известно, что ДНК [8,[21][22][23]25], выделенная из бесклеточной части крови здорового донора, онкологического пациента и больных системной красной волчанкой, также обогащена G/C-парами (43-51% при среднем их содержании в геноме человека 38%). Такое содержание G/C-пар характерно для ДНК, находящейся в составе нуклеосом [26,27].…”

Section: рисунок3unclassified

The value of low-molecular-weight DNA of blood plasma in the diagnostic of the patological processes of different genesis

Васильева

Zinkin²

2013

BIOMED KHIM

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1СПбНИИ Фтизиопульмонологии Росздрава, 191036 Санкт-Петербург, Лиговский пр., 2-4; факс: (812) 297-66-31; эл. почта: nicolaivasiliev@hotmail.com 2 Государственный научно-исследовательский испытательный институт военной медицины МО РФ,127083 Москва, Петровско-Разумовская аллея, д.12 А Низкомолекулярная ДНК появляется в плазме крови через несколько часов после воздействия ионизирующего излучения и её количество пропорционально зависит от дозы. Клонирование показало, что обогащение нуклеотидами C + G и особенности первичной структуры характеризуют способность низкомолекулярной ДНК к образованию стабильных нуклеосом. ДНК, выделенная после облучения в принципиально различных дозах 8 и 100 Гр различается не только количественно, но и по содержанию динуклеотидов СрG и СрТ, что указывает на её происхождение из различных участков генома. Впервые установлено, что воздействие низкочастотного шума приводит к значительному повышению содержания низкомолекулярной ДНК в плазме крови. Инсульты характеризуются увеличением содержания этой ДНК в течение 3 дней после начала острого периода с различной динамикой выделения при ишемическом и геморрагическом типах; при ишемии низкомолекулярная ДНК обнаружена в спинномозговой жидкости. Хроническая обструктивная болезнь лёгких в период ремиссии впервые отмечена снижением уровня низкомолекулярной ДНК плазмы крови, в отличие от хронического необструктивного бронхита. Четкая закономерность образования и особенности структуры низкомолекулярной фракции ДНК плазмы крови позволяют считать её универсальным количественным показателем апоптоза, позволяющим дифференцировать принципиально различные состояния организма.Ключевые слова: низкомолекулярная ДНК, ионизирующее облучение, нуклеосомная организация, низкочастотный шум, ишемический инсульт, хроническая обструктивная болезнь лёгких, апоптоз. 358* -адресат для переписки

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Evolutionary changes in CpG and methylation levels in the genome of vertebrates

Cited by 102 publications

References 56 publications

Conservation of methylation reprogramming in mammalian development: Aberrant reprogramming in cloned embryos

Conservation of methylation reprogramming in mammalian development: Aberrant reprogramming in cloned embryos

The effect of interspecific oocytes on demethylation of sperm DNA

The value of low-molecular-weight DNA of blood plasma in the diagnostic of the patological processes of different genesis

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