TY - JOUR
T1 - Changes in 5S rDNA chromatin organization and transcription during heterochromatin establishment in Arabidopsis.
AU - Mathieu, Olivier
AU - Jasencakova, Zusana
AU - Vaillant, Isabelle
AU - Gendrel, Anne-Valerie
AU - Colot, Vincent
AU - Schubert, Ingo
AU - Tourmente, Sylvette
N1 - Keywords: Arabidopsis; Arabidopsis Proteins; Azacitidine; Cell Nucleus; Chromatin; DNA Methylation; DNA, Ribosomal; DNA-Binding Proteins; Heterochromatin; Histones; Mutation; RNA, Ribosomal, 5S; Time Factors; Transcription Factor TFIIIA; Transcription Factors; Transcription, Genetic
PY - 2003
Y1 - 2003
N2 - In the Arabidopsis accession Columbia, 5S rDNA is located in the pericentromeric heterochromatin of chromosomes 3, 4, and 5. Both a major and some minor 5S rRNA species are expressed from chromosomes 4 and 5, whereas the genes on chromosome 3 are not transcribed. Here, we show that 5S rDNA methylation is reduced in 2-day-old seedlings versus 4-day-old or older aerial plant tissues, and the minor 5S rRNA species are expressed most abundantly at this stage. Similarly, when 5S rDNA is demethylated by 5-azacytidine treatment or via the decrease in DNA methylation1 (ddm1) mutation, the expression of minor 5S rRNA species is increased. We also show that in leaf nuclei of mature wild-type plants, the transcribed fraction of 5S rDNA forms loops that emanate from chromocenters. These loops, which are enlarged in nuclei of mature ddm1 plants, are enriched for histone H3 acetylated at Lys-9 and methylated at Lys-4 compared with the heterochromatic chromocenters. Up to 4 days after germination, heterochromatin is not fully developed: the 5S rDNA resides in prechromocenters, does not form conspicuous loops, and shows the lowest transcription level. Our results indicate that the expression and chromatin organization of 5S rRNA genes change during heterochromatin establishment.
AB - In the Arabidopsis accession Columbia, 5S rDNA is located in the pericentromeric heterochromatin of chromosomes 3, 4, and 5. Both a major and some minor 5S rRNA species are expressed from chromosomes 4 and 5, whereas the genes on chromosome 3 are not transcribed. Here, we show that 5S rDNA methylation is reduced in 2-day-old seedlings versus 4-day-old or older aerial plant tissues, and the minor 5S rRNA species are expressed most abundantly at this stage. Similarly, when 5S rDNA is demethylated by 5-azacytidine treatment or via the decrease in DNA methylation1 (ddm1) mutation, the expression of minor 5S rRNA species is increased. We also show that in leaf nuclei of mature wild-type plants, the transcribed fraction of 5S rDNA forms loops that emanate from chromocenters. These loops, which are enlarged in nuclei of mature ddm1 plants, are enriched for histone H3 acetylated at Lys-9 and methylated at Lys-4 compared with the heterochromatic chromocenters. Up to 4 days after germination, heterochromatin is not fully developed: the 5S rDNA resides in prechromocenters, does not form conspicuous loops, and shows the lowest transcription level. Our results indicate that the expression and chromatin organization of 5S rRNA genes change during heterochromatin establishment.
U2 - 10.1105/tpc.017467
DO - 10.1105/tpc.017467
M3 - Journal article
C2 - 14630972
SN - 1040-4651
VL - 15
SP - 2929
EP - 2939
JO - Plant Cell
JF - Plant Cell
IS - 12
ER -