Complex structure of ATRX ADD domain bound to unmodified H3 1-15 peptide
[ATRX_HUMAN] Defects in ATRX are the cause of alpha-thalassemia mental retardation syndrome X-linked (ATRX) [MIM:301040]. ATR-X is an X-linked disorder comprising severe psychomotor retardation, facial dysmorphism, urogenital abnormalities, and alpha-thalassemia. An essential phenotypic trait are hemoglobin H erythrocyte inclusions.          Defects in ATRX are the cause of mental retardation syndromic X-linked with hypotonic facies syndrome type 1 (MRXSHF1) [MIM:309580]; also called Carpenter-Waziri syndrome (CWS), Juberg-Marsidi syndrome (JMS), Smith-Fineman-Myers syndrome type 1 (SFM1). Clinical features include severe mental retardation, dysmorphic facies, and a highly skewed X-inactivation pattern in carrier women. Other more variable features include hypogonadism, deafness, renal anomalies, and mild skeletal defects.      Defects in ATRX are a cause of alpha-thalassemia myelodysplasia syndrome (ATMDS) [MIM:300448]. In this disorder, alpha-thalassemia occurs as an acquired abnormality in association with a multilineage myelodysplasia.
[ATRX_HUMAN] Could be a global transcriptional regulator. Modifies gene expression by affecting chromatin. May be involved in brain development and facial morphogenesis.
Publication Abstract from PubMed
ATR-X (alpha-thalassemia/mental retardation, X-linked) syndrome is a human congenital disorder that causes severe intellectual disabilities. Mutations in the ATRX gene, which encodes an ATP-dependent chromatin-remodeler, are responsible for the syndrome. Approximately 50% of the missense mutations in affected persons are clustered in a cysteine-rich domain termed ADD (ATRX-DNMT3-DNMT3L, ADD(ATRX)), whose function has remained elusive. Here we identify ADD(ATRX) as a previously unknown histone H3-binding module, whose binding is promoted by lysine 9 trimethylation (H3K9me3) but inhibited by lysine 4 trimethylation (H3K4me3). The cocrystal structure of ADD(ATRX) bound to H3(1-15)K9me3 peptide reveals an atypical composite H3K9me3-binding pocket, which is distinct from the conventional trimethyllysine-binding aromatic cage. Notably, H3K9me3-pocket mutants and ATR-X syndrome mutants are defective in both H3K9me3 binding and localization at pericentromeric heterochromatin; thus, we have discovered a unique histone-recognition mechanism underlying the ATR-X etiology.
ATRX ADD domain links an atypical histone methylation recognition mechanism to human mental-retardation syndrome.,Iwase S, Xiang B, Ghosh S, Ren T, Lewis PW, Cochrane JC, Allis CD, Picketts DJ, Patel DJ, Li H, Shi Y Nat Struct Mol Biol. 2011 Jun 12;18(7):769-76. doi: 10.1038/nsmb.2062. PMID:21666679
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.