Programmed genome rearrangements in Oxytricha produce transcriptionally active extrachromosomal circular DNA.
Nucleic Acids Res
; 47(18): 9741-9760, 2019 10 10.
Article
em En
| MEDLINE
| ID: mdl-31504770
ABSTRACT
Extrachromosomal circular DNA (eccDNA) is both a driver of eukaryotic genome instability and a product of programmed genome rearrangements, but its extent had not been surveyed in Oxytricha, a ciliate with elaborate DNA elimination and translocation during development. Here, we captured rearrangement-specific circular DNA molecules across the genome to gain insight into its processes of programmed genome rearrangement. We recovered thousands of circularly excised Tc1/mariner-type transposable elements and high confidence non-repetitive germline-limited loci. We verified their bona fide circular topology using circular DNA deep-sequencing, 2D gel electrophoresis and inverse polymerase chain reaction. In contrast to the precise circular excision of transposable elements, we report widespread heterogeneity in the circular excision of non-repetitive germline-limited loci. We also demonstrate that circular DNAs are transcribed in Oxytricha, producing rearrangement-specific long non-coding RNAs. The programmed formation of thousands of eccDNA molecules makes Oxytricha a model system for studying nucleic acid topology. It also suggests involvement of eccDNA in programmed genome rearrangement.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Recombinação Genética
/
DNA Circular
/
Rearranjo Gênico
/
Oxytricha
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Estados Unidos