DNA methylation in the promoter of ribosomal RNA genes in human cells as determined by genomic sequencing

FEBS Letters

Doerfler, Walter¹  Schiedner, Gudrun¹  Hosokawa, Keiichi²  Kochanek, Stefan¹  Renz, Doris¹ 

[1] Division of Medical Genetics and Virology, Institute of Genetics, University of Cologne, Weyertal 121, D-50931 Cologne, Germany;Department of Biochemistry, Kawasaki Medical School, Kurashiki, Okayama, Japan

关键词: Genomic sequencing;    DNA methylation;    RNA polymerase I;    Ribosomal RNA genes;    rDNA;   

DOI  :  10.1016/0014-5793(96)00506-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Many RNA polymerase II- or III-transcribed genes are inactive when their promoter is methylated at critical CpG dinucleotides. We have applied the genomic sequencing method and a direct DNA blotting technique to analyze the extent of DNA methylation in the 5′-CpG-3′ rich promoter region of the RNA polymerase I-transcribed ribosomal RNA genes (rDNA) in DNA from primary human cells, primary human tumor cells and human cell lines. In none of the analyzed primary human cells and primary human tumor cells was the DNA in the rDNA promoter region found to be detectably methylated. In contrast, in some of the cell lines this promoter is methylated in all 5′-CpG-3′ dinucleotides in the majority of the approximately 200 ribosomal RNA gene copies. In actively growing cells, rDNA gene activity is a prerequisite for cell viability. The high levels of DNA methylation in the promoter region of rDNA in the human cell lines raise questions on the role of promoter methylation in these RNA polymerase I-transcribed genes. It is, however, conceivable that a subset of the about 200 rDNA copies per haploid genome have escaped methylation and account for the rRNA synthesis in these cell lines. Alternatively, complete 5′-CpG-3′ promoter methylation may be compatible with promoter activity as demonstrated for certain viral genomes.

【 授权许可】

Unknown