Activation of the maternally preset program of apoptosis by microinjection of 5-aza-2'-deoxycytidine and 5-methyl-2'-deoxycytidine-5'-triphosphate in Xenopus laevis embryos
| Autor: | Masatake Kai, Chikara Kaito, Koichiro Shiokawa, Kazuhisa Sekimizu, Eiji Takayama, Hiroshi Fukamachi, Takayasu Higo |
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| Rok vydání: | 2001 |
| Předmět: |
Embryo
Nonmammalian Microinjections Xenopus Apoptosis DNA Fragmentation Biology Decitabine Deoxycytidine Midblastula Xenopus laevis chemistry.chemical_compound In Situ Nick-End Labeling Animals heterocyclic compounds DNA Modification Methylases DNA synthesis DNA replication Cell Biology DNA Methylation biology.organism_classification Molecular biology Chromatin Proto-Oncogene Proteins c-bcl-2 chemistry DNA methylation Azacitidine Oocytes DNA fragmentation Female DNA Developmental Biology |
| Zdroj: | Web of Science |
| ISSN: | 1440-169X 0012-1592 |
| DOI: | 10.1046/j.1440-169x.2001.00579.x |
| Popis: | The present study examines the effects on embryogenesis of microinjecting Xenopus laevis fertilized eggs with 5-aza-2'-deoxycytidine (5-Aza-CdR), which induces hypomethylation of DNA, and 5-methyl-2'- deoxycytidine-5'-triphosphate (5-methyl-dCTP), which induces hypermethylation of DNA. Embryos injected with either one of these analogs cleaved normally until the mid-blastula stage, but underwent massive cell dissociation and stopped development at the early gastrula stage. Dissociated cells that appeared here were positive by terminal deoxyribonucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end-labeling and contained fragmented nuclei with condensed chromatin. The DNA from these cells formed a "ladder" on electrophoresis. Furthermore, the induction of cell dissociation by 5-Aza-CdR and 5-methyl-dCTP was postponed by 2-3 h by co-injection of Bcl-2 mRNA and the normal metabolite (CdR and dCTP, respectively). Using a specific antibody against 5-methyl-cytosine, we confirmed that 5-Aza-CdR induces hypomethylation, whereas 5-methyl-dCTP induces hypermethylation in X. laevis embryos before the onset of cell dissociation. Incorporation of radioactive precursors revealed that synthesis of DNA, and also RNA, is inhibited significantly in both 5-Aza-CdR-injected and 5-methyl-dCTP-injected embryos. These results show that 5-Aza-CdR and 5-methyl-dCTP are incorporated into DNA and induce apoptosis, probably through alteration of DNA methylation coupled with inhibition of DNA replication and/or transcription. |
| Databáze: | OpenAIRE |
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