RESUMEN
We have established a landmark framework map over 20-25 Mb of the long arm of the human X chromosome using yeast artificial chromosome (YAC) clones. The map has approximately one landmark per 45 kb of DNA and stretches from DXS7531 in proximal Xq23 to DXS895 in proximal Xq26, connecting to published framework maps on its proximal and distal sides. There are three gaps in the framework map resulting from the failure to obtain clone coverage from the YAC resources available. Estimates of the maximum sizes of these gaps have been obtained. The four YAC contigs have been positioned and oriented using somatic-cell hybrids and fluorescence in situ hybridization, and the largest is estimated to cover approximately 15 Mb of DNA. The framework map is being used to assemble a sequence-ready map in large-insert bacterial clones, as part of an international effort to complete the sequence of the X chromosome. PAC and BAC contigs currently cover 18 Mb of the region, and from these, 12 Mb of finished sequence is available.
Asunto(s)
Mapeo Cromosómico/métodos , Cromosoma X/genética , Southern Blotting , Cromosomas Artificiales de Levadura/genética , Mapeo Contig , Electroforesis en Gel de Campo Pulsado , Femenino , Marcadores Genéticos/genética , Humanos , Hibridación Fluorescente in Situ , Análisis de Secuencia de ADNRESUMEN
Thiazolidinediones are a new class of antidiabetic agent that improve insulin sensitivity and reduce plasma glucose and blood pressure in subjects with type 2 diabetes. Although these agents can bind and activate an orphan nuclear receptor, peroxisome proliferator-activated receptor gamma (PPARgamma), there is no direct evidence to conclusively implicate this receptor in the regulation of mammalian glucose homeostasis. Here we report two different heterozygous mutations in the ligand-binding domain of PPARgamma in three subjects with severe insulin resistance. In the PPARgamma crystal structure, the mutations destabilize helix 12 which mediates transactivation. Consistent with this, both receptor mutants are markedly transcriptionally impaired and, moreover, are able to inhibit the action of coexpressed wild-type PPARgamma in a dominant negative manner. In addition to insulin resistance, all three subjects developed type 2 diabetes mellitus and hypertension at an unusually early age. Our findings represent the first germline loss-of-function mutations in PPARgamma and provide compelling genetic evidence that this receptor is important in the control of insulin sensitivity, glucose homeostasis and blood pressure in man.
Asunto(s)
Diabetes Mellitus Tipo 2/etiología , Hipertensión/etiología , Resistencia a la Insulina , Mutación , Receptores Citoplasmáticos y Nucleares/fisiología , Tiazolidinedionas , Factores de Transcripción/fisiología , Adulto , Animales , Benzoxazoles/metabolismo , Sitios de Unión , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/genética , Femenino , Genes Dominantes , Humanos , Hipertensión/complicaciones , Hipertensión/genética , Resistencia a la Insulina/genética , Ligandos , Masculino , Ratones , Persona de Mediana Edad , Modelos Moleculares , Ácidos Nicotínicos/metabolismo , Fenilpropionatos/metabolismo , Conformación Proteica , Receptores Citoplasmáticos y Nucleares/química , Receptores Citoplasmáticos y Nucleares/genética , Receptores de Ácido Retinoico/metabolismo , Receptores X Retinoide , Rosiglitazona , Tetrahidronaftalenos/metabolismo , Tiazoles/metabolismo , Factores de Transcripción/química , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Our aim is to construct physical clone maps covering those regions of chromosome 6 that are not currently extensively mapped, and use these to determine the DNA sequence of the whole chromosome. The strategy we are following involves establishing a high density framework map of the order of 15 markers per Megabase using radiation hybrid (RH) mapping. The markers are then used to identify large-insert genomic bacterial clones covering the chromosome, which are assembled into sequence-ready contigs by restriction enzyme fingerprinting and sequence tagged site (STS) content analysis. Contig gap closure is performed by walking experiments using STSs developed from the end sequences of the clone inserts.
Asunto(s)
Cromosomas Humanos Par 6/genética , Mapeo Contig , Bases de Datos Factuales , Humanos , Análisis de Secuencia de ADNRESUMEN
The Sanger Centre Chromosome 6 Database (6ace) has been developed as the primary means of release of annotated sequencing and mapping information for human chromosome 6 from the Sanger Centre. It is also being used to curate global data from published and unpublished external sources. The rationale behind the development of 6ace is described, together with information as to how to access the database.
Asunto(s)
Cromosomas Humanos Par 6/genética , Bases de Datos Factuales , Secuencia de Bases , Humanos , Internet , Datos de Secuencia MolecularRESUMEN
The development of radiation hybrid (RH) mapping (Cox et al., 1990) and the availability of large numbers of STS markers, together with extensive bacterial clone resources provided a means to accelerate the process of mapping a human chromosome and preparing bacterial clone contigs ready to sequence. Our aim is to construct physical clone maps covering those regions of chromosome 6 that are not currently extensively mapped, and use these to determine the DNA sequence of the whole chromosome. We report here a strategy which initially involves establishing a high density framework map using RH mapping. The framework markers are then used for the identification of bacterial genomic clones covering the chromosome. The bacterial clones are analysed by restriction enzyme fingerprinting and STS-content analysis to identify sequence-ready contigs. Contig gap closure will also be performed by clone walking.
Asunto(s)
Mapeo Cromosómico/métodos , Cromosomas Humanos Par 6/genética , Análisis de Secuencia de ADN/métodos , Clonación Molecular , Dermatoglifia del ADN/métodos , ADN Complementario , Expresión Génica , Marcadores Genéticos , Vectores Genéticos , HumanosAsunto(s)
Cromosomas Artificiales de Levadura , Sistemas de Administración de Bases de Datos , Bases de Datos Factuales , Biblioteca de Genes , Secuencia de Bases , Cromosomas Humanos Par 22 , Redes de Comunicación de Computadores , Alfabetización Digital , Computadores , Humanos , Datos de Secuencia MolecularRESUMEN
We have constructed a high-resolution clone map of human chromosome 22 which integrates the available physical and genetic information, establishing a single consensus. The map consists of all classes of DNA landmarks ordered on 705 yeast artificial chromosomes (YACs) at an average landmark density of more than one per 70 kilobases. This map represents the practical limits of currently available YAC resources and provides the basis for determination of the entire gene content and genomic DNA sequence of human chromosome 22.
Asunto(s)
Cromosomas Artificiales de Levadura , Cromosomas Humanos Par 22 , Mapeo Cromosómico/métodos , Marcadores Genéticos , Humanos , Lugares Marcados de SecuenciaRESUMEN
We demonstrate that all the repeat elements representing the conserved loci DXF34 and DXS390 lie between the X;9 and the X;17 translocation breakpoints associated with incontinentia pigmenti type 1 (IP1). Sequence-tagged sites (STSs) at DXF34S1, DXS14, and DXS390 have been used to isolate YAC clones containing these loci, and a contig of approximately 2 Mb has been constructed. Patterns of hybridization observed in the YAC clones indicate that DXS390 comprises two distinct regions (A and B). The STS at DXS390 detects the A region and includes a polymorphic CA repeat (PIC = 0.25). This expansion of the cloned region around DXF34 and DXS390 will enable the isolation of additional conserved sequences that will help in understanding both the lesions underlying the pathogenesis of IP1 and the size and extent of the man-mouse homologous block defined by DXF34.
Asunto(s)
Cromosomas Humanos Par 17 , Cromosomas Humanos Par 9 , Incontinencia Pigmentaria/genética , Translocación Genética , Cromosoma X , Animales , Secuencia de Bases , Línea Celular , Mapeo Cromosómico , Cromosomas Artificiales de Levadura , Secuencia Conservada , Cartilla de ADN , Marcadores Genéticos , Humanos , Células Híbridas , Ratones , Datos de Secuencia Molecular , Sondas de Oligonucleótidos , Reacción en Cadena de la Polimerasa , Mapeo RestrictivoRESUMEN
The gastrin-releasing peptide receptor has been previously cloned from both humans and mice. We have mapped the mouse gastrin-releasing peptide receptor (Grpr) locus using a polymorphic CAn repeat located in the 5' untranslated region of the gene and a Mus spretus/Mus musculus interspecific backcross. The Grpr locus mapped between the Pdha-1 and Amg loci on the mouse X chromosome. Studies in man indicate that GRPR maps to the Xp21.2-p22.3 region of the human X chromosome and not to the Xp11-q11 interval as previously reported. The assignment of the GRPR locus to the distal Xp region is supported by the comparative map position in the mouse.
