RESUMO
The long non-coding RNA X-inactive specific transcript (XIST) mediates the transcriptional silencing of genes on the X chromosome. Here we show that, in human cells, XIST is highly methylated with at least 78 N6-methyladenosine (m6A) residues-a reversible base modification of unknown function in long non-coding RNAs. We show that m6A formation in XIST, as well as in cellular mRNAs, is mediated by RNA-binding motif protein 15 (RBM15) and its paralogue RBM15B, which bind the m6A-methylation complex and recruit it to specific sites in RNA. This results in the methylation of adenosine nucleotides in adjacent m6A consensus motifs. Furthermore, we show that knockdown of RBM15 and RBM15B, or knockdown of methyltransferase like 3 (METTL3), an m6A methyltransferase, impairs XIST-mediated gene silencing. A systematic comparison of m6A-binding proteins shows that YTH domain containing 1 (YTHDC1) preferentially recognizes m6A residues on XIST and is required for XIST function. Additionally, artificial tethering of YTHDC1 to XIST rescues XIST-mediated silencing upon loss of m6A. These data reveal a pathway of m6A formation and recognition required for XIST-mediated transcriptional repression.
Assuntos
Adenosina/análogos & derivados , Inativação Gênica , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Transcrição Gênica , Adenosina/metabolismo , Animais , Proteínas de Ciclo Celular , Linhagem Celular , Células-Tronco Embrionárias/metabolismo , Feminino , Células HEK293 , Humanos , Masculino , Metilação , Metiltransferases/metabolismo , Camundongos , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Processamento de RNA/metabolismo , Proteínas de Ligação a RNA/metabolismoRESUMO
Nil.
Assuntos
COVID-19 , Humanos , Nova Zelândia/epidemiologia , Surtos de Doenças/prevenção & controle , Instituições AcadêmicasRESUMO
The Xist long noncoding RNA orchestrates X chromosome inactivation, a process that entails chromosome-wide silencing and remodeling of the three-dimensional (3D) structure of the X chromosome. Yet, it remains unclear whether these changes in nuclear structure are mediated by Xist and whether they are required for silencing. Here, we show that Xist directly interacts with the Lamin B receptor, an integral component of the nuclear lamina, and that this interaction is required for Xist-mediated silencing by recruiting the inactive X to the nuclear lamina and by doing so enables Xist to spread to actively transcribed genes across the X. Our results demonstrate that lamina recruitment changes the 3D structure of DNA, enabling Xist and its silencing proteins to spread across the X to silence transcription.