6tl1 | pdb_00006tl1
Crystal structure of the TASOR pseudo-PARP domain
Structural highlights
Function[TASOR_HUMAN] Component of the HUSH complex, a multiprotein complex that mediates epigenetic repression (PubMed:26022416, PubMed:28581500). The HUSH complex is recruited to genomic loci rich in H3K9me3 and is required to maintain transcriptional silencing by promoting recruitment of SETDB1, a histone methyltransferase that mediates further deposition of H3K9me3, as well as MORC2 (PubMed:26022416, PubMed:28581500). Also represses L1 retrotransposons in collaboration with MORC2 and, probably, SETDB1, the silencing is dependent of repressive epigenetic modifications, such as H3K9me3 mark. Silencing events often occur within introns of transcriptionally active genes, and lead to the down-regulation of host gene expression (PubMed:29211708). The HUSH complex is also involved in the silencing of unintegrated retroviral DNA by being recruited by ZNF638: some part of the retroviral DNA formed immediately after infection remains unintegrated in the host genome and is transcriptionally repressed (PubMed:30487602). Plays a crucial role in early embryonic development (By similarity). Involved in the organization of spindle poles and spindle apparatus assembly during zygotic division (By similarity). Plays an important role in maintaining epiblast fitness or potency (By similarity).[UniProtKB:Q69ZR9][1] [2] [3] [4] Publication Abstract from PubMedThe HUSH complex represses retroviruses, transposons and genes to maintain the integrity of vertebrate genomes. HUSH regulates deposition of the epigenetic mark H3K9me3, but how its three core subunits - TASOR, MPP8 and Periphilin - contribute to assembly and targeting of the complex remains unknown. Here, we define the biochemical basis of HUSH assembly and find that its modular architecture resembles the yeast RNA-induced transcriptional silencing complex. TASOR, the central HUSH subunit, associates with RNA processing components. TASOR is required for H3K9me3 deposition over LINE-1 repeats and repetitive exons in transcribed genes. In the context of previous studies, this suggests that an RNA intermediate is important for HUSH activity. We dissect the TASOR and MPP8 domains necessary for transgene repression. Structure-function analyses reveal TASOR bears a catalytically-inactive PARP domain necessary for targeted H3K9me3 deposition. We conclude that TASOR is a multifunctional pseudo-PARP that directs HUSH assembly and epigenetic regulation of repetitive genomic targets. TASOR is a pseudo-PARP that directs HUSH complex assembly and epigenetic transposon control.,Douse CH, Tchasovnikarova IA, Timms RT, Protasio AV, Seczynska M, Prigozhin DM, Albecka A, Wagstaff J, Williamson JC, Freund SMV, Lehner PJ, Modis Y Nat Commun. 2020 Oct 2;11(1):4940. doi: 10.1038/s41467-020-18761-6. PMID:33009411[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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