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In the originally published version of this Letter, the authors Arthur F. Kluge, Michael A. Patane and Ce Wang were inadvertently omitted from the author list. Their affiliations are: I-to-D, Inc., PO Box 6177, Lincoln, Massachusetts 01773, USA (A.F.K.); Mitobridge, Inc. 1030 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA (M.A.P.); and China Novartis Institutes for BioMedical Research, No. 4218 Jinke Road, Zhangjiang Hi-Tech Park, Pudong District, Shanghai 201203, China (C.W.). These authors contributed to the interpretation of results and design of compounds. In addition, author 'Edward A. Kesicki' was misspelled as 'Ed Kesicki'. These errors have been corrected online.

p300 and its paralog CBP can acetylate histones and other proteins and have been implicated in a number of diseases characterized by aberrant gene activation, such as cancer. A novel, highly selective, orally bioavailable histone acetyltransferase (HAT) domain inhibitor has been identified through virtual ligand screening and subsequent optimization of a unique hydantoin screening hit. Conformational restraint in the form of a spirocyclization followed by substitution with a urea led to a significant improvement in potency. Replacement of the hydantoin moiety with an oxazolidinedione followed by fluoro substitution led to A-485 , which exhibits potent cell activity, low clearance, and high oral bioavailability., Competing Interests: The authors declare the following competing financial interest(s): This study was sponsored by AbbVie. AbbVie contributed to the study design, research, and interpretation of data, writing, reviewing, and approving the publication. M.R.M., T.M.H., R.M.R., R.Man., H.L., K.D.B., L.L., and A.L. are employees of AbbVie. D.M., E.A.K., K.K., P.d.V., and J.W.L were employees of Acylin, which provided assets to Abbvie at the time of the study. R.Mar. and P.A.C. are co-founders of Acylin and consultants for AbbVie.

The dynamic and reversible acetylation of proteins, catalysed by histone acetyltransferases (HATs) and histone deacetylases (HDACs), is a major epigenetic regulatory mechanism of gene transcription and is associated with multiple diseases. Histone deacetylase inhibitors are currently approved to treat certain cancers, but progress on the development of drug-like histone actyltransferase inhibitors has lagged behind. The histone acetyltransferase paralogues p300 and CREB-binding protein (CBP) are key transcriptional co-activators that are essential for a multitude of cellular processes, and have also been implicated in human pathological conditions (including cancer). Current inhibitors of the p300 and CBP histone acetyltransferase domains, including natural products, bi-substrate analogues and the widely used small molecule C646, lack potency or selectivity. Here, we describe A-485, a potent, selective and drug-like catalytic inhibitor of p300 and CBP. We present a high resolution (1.95 Å) co-crystal structure of a small molecule bound to the catalytic active site of p300 and demonstrate that A-485 competes with acetyl coenzyme A (acetyl-CoA). A-485 selectively inhibited proliferation in lineage-specific tumour types, including several haematological malignancies and androgen receptor-positive prostate cancer. A-485 inhibited the androgen receptor transcriptional program in both androgen-sensitive and castration-resistant prostate cancer and inhibited tumour growth in a castration-resistant xenograft model. These results demonstrate the feasibility of using small molecule inhibitors to selectively target the catalytic activity of histone acetyltransferases, which may provide effective treatments for transcriptional activator-driven malignancies and diseases.

A physical map of 4q35 was constructed through radiation hybrid analysis of 134 clones generated from the cell line HHW416, a chromosome 4-only human-hamster somatic cell hybrid. This subtelomeric region contains the as-yet-unidentified gene responsible for facioscapulohumeral muscular dystrophy. The most likely order of 15 loci within 4q35 was determined. The loci ordered on this radiation hybrid map include both genes and polymorphic loci, as well as monomorphic loci which cannot be placed on a genetic linkage map. The physical distance spanning these loci was estimated to be approximately 4.5 Mb, by using a kilobase/centiray conversion factor derived from 4p16.3 marker analysis through the same set of radiation hybrids. The comparison of this physical map to establish genetic maps suggests that this region is smaller than initially estimated and that recombination rates are increased near the telomere.

The gene encoding the D2 dopamine receptor (DRD2) is located on human chromosome 11q23 and has been circumstantially associated with a number of human disorders including Parkinson's disease, schizophrenia, and susceptibility to alcoholism. To determine the physical structure of the DRD2 gene, we utilized cosmid cloning, isolation of yeast artificial chromosomes (YACs), and pulsed-field gel electrophoresis to construct a long-range physical map of human chromosome 11q23 linking the genes for the DRD2 and neural cell adhesion molecule (NCAM). The D2 dopamine receptor gene extends over 270 kb and includes an intron of approximately 250 kb separating the putative first exon from the exons encoding the receptor protein. The resulting physical map spans more than 1.5 mb of chromosome band 11q23 and links the DRD2 gene with the gene encoding the NCAM located 150 kb 3' of the DRD2 gene and transcribed from the same DNA strand. We additionally located the sites of at least four hypomethylated HTF islands within the physical map, which potentially indicate the sites of additional genes. High-resolution fluorescent in situ suppression hybridization using cosmid and YAC clones localized this gene cluster between the ApoAI and STMY loci at the interface of bands 11q22.3 and 11q23.1.

"Chimeric" yeast artificial chromosomes (YACs) are clones containing two or more noncontiguous segments of DNA and represent the most common artifact found in total genomic YAC libraries currently used for large-scale genome mapping. These YACs create spurious mapping information that complicates the construction of YAC contigs and leads to erroneous maps during chromosome walks. The presence of these artifactual clones necessitates laborious and time-consuming characterization of each isolated YAC clone, either by comparison of the physical map of the YAC with the corresponding source genomic DNA, or by demonstrating discrepant chromosomal origins for the two ends of the YAC by hybridization or polymerase chain reaction (PCR). Here, we describe a rapid and sensitive method for the assessment of YAC colinearity by fluorescence in situ suppression hybridization (FISSH) by utilizing fluorescein-12-dUTP for labeling YAC clones. We have analyzed 51 YACs and found that 43% (22 out of 51) are chimeric and significantly larger (302 kb) than colinear ones (228 kb). One of the 51 YAC clones (2%) examined contains portions of three chromosomes and 2 (4%) seem to map to a chromosome different than that of the identifying STS. FISSH analysis offers a straightforward visualization of the entire YAC insert on the chromosomes and can be used to examine many YACs simultaneously in few days.

Yeast artificial chromosomes (YACs) provide a powerful tool for the isolation and mapping of large regions of mammalian chromosomes. We developed a rapid and efficient method for the isolation of DNA fragments representing the extreme ends of YAC clones by the insertion of a rescue plasmid into the YAC vector by homologous recombination. Two rescue vectors were constructed containing a yeast LYS2 selectable gene, a bacterial origin of replication, an antibiotic resistance gene, a polylinker containing multiple restriction sites, and a fragment homologous to one arm of the pYAC4 vector. The 'end-cloning' procedure involves transformation of the rescue vector into yeast cells carrying a YAC clone, followed by preparation of yeast DNA and transformation into bacterial cells. The resulting plasmids carry end-specific DNA fragments up to 20 kb in length, which are suitable for use as hybridization probes, as templates for direct DNA sequencing, and as probes for mapping by fluorescence in situ hybridization. These vectors are suitable for the rescue of end-clones from any YAC constructed using a pYAC-derived vector. We demonstrate the utility of these plasmids by rescuing YAC-end fragments from a human YAC library.

The derived amino-acid sequences of the heterodimeric antigen receptors expressed by a series of murine T-cell clones are presented. A comparison of the receptor sequences indicates that several mechanisms for generating receptor diversity can influence T-cell specificity, including junctional diversity, combinatorial joining, and combinatorial chain associations.

The induction of an immune response in mammals is initiated by specifically reactive T lymphocytes. The specificity of the reaction is mediated by a complex receptor, part of which is highly variable in sequence and analogous to immunoglobulin heavy- and light-chain variable domains. The functional specificity of the T cell antigen receptor is, however, markedly different from immunoglobulins in that it mediates cell-cell interactions via the simultaneous recognition of foreign antigens and major histocompatibility complex-encoded molecules expressed on the surface of various lymphoid and nonlymphoid cells. The relation between the structure of the receptor and its functional specificity was investigated by analyzing the primary sequences of the receptors expressed by a series of T lymphocyte clones specific for a model antigen, pigeon cytochrome c. Within this set of T lymphocyte clones there was a striking selection for amino acid sequences in the receptor beta-chain in the region analogous to the third complementarity-determining region of immunoglobulins. Thus, despite the functional differences between T cell antigen receptors and immunoglobulin molecules, analogous regions appear to be important in determining ligand specificity.