Methylation Induced Premeiotically in Ascobolus: Coextension with DNA Repeat Lengths and Effect on Transcript Elongation

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 90; no. 10; pp. 4557 - 4561
• Main Authors: Barry, Caroline, Faugeron, Godeleine, Rossignol, Jean-Luc
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 15-05-1993; National Acad Sciences; National Academy of Sciences
• Subjects: 5-Methylcytosine; Asci; Biological and medical sciences; Cytosine - analogs & derivatives; Cytosine - metabolism; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA - metabolism; Fundamental and applied biological sciences. Psychology; Fungi; Fungi - genetics; Gels; Gene Expression Regulation, Fungal; Genes; Genes, Fungal; Genetic mutation; Genetics; Meiosis; Methylation; Molecular and cellular biology; Molecular genetics; Open reading frames; Phenotypes; Repetitive Sequences, Nucleic Acid; Restriction Mapping; Reverse transcriptase polymerase chain reaction; RNA; RNA, Messenger - genetics; Transcription, Genetic; Transcription. Transcription factor. Splicing. Rna processing; Fungi; Transcription; DNA; Nucleotide fragment; Ascomycetes; Ascobolus immersus; Gene duplication; Meiosis; Inhibition; Methylation; Thallophyta
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.90.10.4557

The effect of duplications of gene fragments on the triggering of DNA methylation induced premeiotically (MIP) was studied in the sexual progeny of strains harboring, in addition to the resident met2 gene, a fragment of this gene inserted at an ectopic position. Cytosine methylation of the resident gene was checked for each of the eight duplications tested. Methylation was always found and it was coextensive with the length of the duplications. Silencing of the resident gene was triggered by duplications of segments corresponding to the region 5' to the open reading frame, to only the open reading frame, or to segments beginning 0.87-1.2 kb down-stream from the transcription start. Silencing was accompanied by either the absence of transcripts or the presence of truncated transcripts, which suggests that methylation acts on transcript elongation.