Xist Repeats A and B Account for Two Distinct Phases of X Inactivation Establishment.
Dev Cell
; 54(1): 21-32.e5, 2020 07 06.
Article
en En
| MEDLINE
| ID: mdl-32531209
ABSTRACT
X chromosome inactivation (XCI) is a global silencing mechanism by which XX and XY mammals equalize X-linked gene dosages. XCI begins with an establishment phase during which Xist RNA spreads and induces de novo heterochromatinization across a female X chromosome and is followed by a maintenance phase when multiple epigenetic pathways lock down the inactive X (Xi) state. Involvement of Polycomb repressive complexes 1 and 2 in XCI has been intensively studied but with conflicting conclusions regarding their recruitment and role in Xi silencing. Here, we reveal that establishment of XCI has two phases and reconcile the roles that Xist repeats A and B play in gene silencing and Polycomb recruitment. Repeat A initiates both processes, whereas repeat B bolsters or stabilizes them thereafter. Once established, XCI no longer requires repeat A during maintenance. These findings integrate disparate studies and present a unified view of Xist's role in Polycomb-mediated silencing.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Inactivación del Cromosoma X
/
Proteínas del Grupo Polycomb
/
ARN Largo no Codificante
Límite:
Animals
Idioma:
En
Revista:
Dev Cell
Asunto de la revista:
EMBRIOLOGIA
Año:
2020
Tipo del documento:
Article
País de afiliación:
Estados Unidos