RESUMEN

The ATRX ATP-dependent chromatin remodelling/helicase protein associates with the DAXX histone chaperone to deposit histone H3.3 over repetitive DNA regions. Because ATRX-protein interactions impart functions, such as histone deposition, we used proximity-dependent biotinylation (BioID) to identify proximal associations for ATRX. The proteomic screen captured known interactors, such as DAXX, NBS1, and PML, but also identified a range of new associating proteins. To gauge the scope of their roles, we examined three novel ATRX-associating proteins that likely differed in function, and for which little data were available. We found CCDC71 to associate with ATRX, but also HP1 and NAP1, suggesting a role in chromatin maintenance. Contrastingly, FAM207A associated with proteins involved in ribosome biosynthesis and localized to the nucleolus. ATRX proximal associations with the SLF2 DNA damage response factor help inhibit telomere exchanges. We further screened for the proteomic changes at telomeres when ATRX, SLF2, or both proteins were deleted. The loss caused important changes in the abundance of chromatin remodelling, DNA replication, and DNA repair factors at telomeres. Interestingly, several of these have previously been implicated in alternative lengthening of telomeres. Altogether, this study expands the repertoire of ATRX-associating proteins and functions.

Asunto(s)

Proteínas Co-Represoras/genética , Proteínas de Unión al ADN/genética , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas Nucleares/genética , Proteína Nuclear Ligada al Cromosoma X/genética , Biotinilación/genética , Proteínas de Ciclo Celular/genética , Línea Celular , Cromatina/genética , Homólogo de la Proteína Chromobox 5/genética , Daño del ADN/genética , Reparación del ADN/genética , Chaperonas de Histonas/genética , Histonas/genética , Humanos , Chaperonas Moleculares/genética , Proteína de la Leucemia Promielocítica/genética , Telómero/genética , ARNt Metiltransferasas