PAR-TERRA directs homologous sex chromosome pairing.
Nat Struct Mol Biol
; 24(8): 620-631, 2017 Aug.
Article
em En
| MEDLINE
| ID: mdl-28692038
ABSTRACT
In mammals, homologous chromosomes rarely pair outside meiosis. One exception is the X chromosome, which transiently pairs during X-chromosome inactivation (XCI). How two chromosomes find each other in 3D space is not known. Here, we reveal a required interaction between the X-inactivation center (Xic) and the telomere in mouse embryonic stem (ES) cells. The subtelomeric, pseudoautosomal regions (PARs) of the two sex chromosomes (X and Y) also undergo pairing in both female and male cells. PARs transcribe a class of telomeric RNA, dubbed PAR-TERRA, which accounts for a vast majority of all TERRA transcripts. PAR-TERRA binds throughout the genome, including to the PAR and Xic. During X-chromosome pairing, PAR-TERRA anchors the Xic to the PAR, creating a 'tetrad' of pairwise homologous interactions (Xic-Xic, PAR-PAR, and Xic-PAR). Xic pairing occurs within the tetrad. Depleting PAR-TERRA abrogates pairing and blocks initiation of XCI, whereas autosomal PAR-TERRA induces ectopic pairing. We propose a 'constrained diffusion model' in which PAR-TERRA creates an interaction hub to guide Xic homology searching during XCI.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cromossomos Sexuais
/
Fatores de Transcrição
/
Pareamento Cromossômico
/
Proteínas de Ligação a DNA
/
Inativação do Cromossomo X
/
Regiões Pseudoautossômicas
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Nat Struct Mol Biol
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Estados Unidos