Transcription of the 5S rRNA heterochromatic genes is epigenetically controlled in Arabidopsis thaliana and Xenopus laevis.
5S ribosomal DNA is a highly conserved tandemly repeated multigenic family. As suggested for a long time, we have shown that only a fraction of the 5S rRNA genes are expressed in Arabidopsis thaliana. In Xenopus laevis, there is a developmental control of the expression of the 5S rRNA genes with only one of the two 5S rDNA families expressed during oogenesis. For both Arabidopsis and Xenopus, the strongest transcription of 5S rRNA, respectively in the seed and during oogenesis is correlated with heterogeneity in the transcribed 5S rRNAs. Epigenetic mechanisms such as modification of the chromatin structure are involved in the transcriptional regulation of the 5S rRNA genes in both organisms. In Arabidopsis, two silencing pathways, methylation-dependent (RNAi) and methylation-independent (MOM pathway), are involved in the silencing of a 5S rDNA fraction.
Douet
J
J
Unité Mixte de Recherche CNRS 6547 BIOMOVE, Université Blaise Pascal, Aubière Cedex, France.
Tourmente
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D000074183:ATPases Associated with Diverse Cellular Activities; D000818:Animals; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant; D006570:Heterochromatin / Q000235:genetics*; D009687:Nuclear Proteins / Q000378:metabolism; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014982:Xenopus laevis / Q000235:genetics* / Q000254:growth & development
D029681:Arabidopsis Proteins; D002843:Chromatin; D006570:Heterochromatin; D009687:Nuclear Proteins; D012341:RNA, Ribosomal, 5S; D014157:Transcription Factors; D000074183:ATPases Associated with Diverse Cellular Activities; C409208:MOM protein, Arabidopsis