RESUMEN
Type 2 diabetes (T2D) is a common, polygenic chronic disease with high heritability. The purpose of this whole-genome association study was to discover novel T2D-associated genes. We genotyped 500 familial cases and 497 controls with >300,000 HapMap-derived tagging single-nucleotide-polymorphism (SNP) markers. When a stringent statistical correction for multiple testing was used, the only significant SNP was at TCF7L2, which has already been discovered and confirmed as a T2D-susceptibility gene. For a replication study, we selected 10 SNPs in six chromosomal regions with the strongest association (singly or as part of a haplotype) for retesting in an independent case-control set including 2,573 T2D cases and 2,776 controls. The most significant replicated result was found at the AHI1-LOC441171 gene region.
Asunto(s)
Diabetes Mellitus Tipo 2/genética , Frecuencia de los Genes , Desequilibrio de Ligamiento , Polimorfismo de Nucleótido Simple , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras del Transporte Vesicular , Estudios de Casos y Controles , Inglaterra , Femenino , Finlandia , Predisposición Genética a la Enfermedad , Genoma Humano , Alemania , Humanos , Israel , Judíos/genética , Masculino , Población BlancaRESUMEN
Bacteriophage PM2 presently is the only member of the Corticoviridae family. The virion consists of a protein-rich lipid vesicle, which is surrounded by an icosahedral protein capsid. The lipid vesicle encloses a supercoiled circular double-stranded DNA genome of 10,079 bp. PM2 belongs to the marine phage community and is known to infect two gram-negative Pseudoalteromonas species. In this study, we present a characterization of the PM2 genome made using the in vitro transposon insertion mutagenesis approach. Analysis of 101 insertion mutants yielded information on the essential and dispensable regions of the PM2 genome and led to the identification of several new genes. A number of lysis-deficient mutants as well as mutants displaying delayed- and/or incomplete-lysis phenotypes were identified. This enabled us to identify novel lysis-associated genes with no resemblance to those previously described from other bacteriophage systems. Nonessential genome regions are discussed in the context of PM2 genome evolution.
Asunto(s)
Corticoviridae/genética , Elementos Transponibles de ADN , Lípidos/química , Mutagénesis , Secuencia de Aminoácidos , ADN/genética , Evolución Molecular , Genoma , Genoma Viral , Metabolismo de los Lípidos , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Fenotipo , PseudoalteromonasRESUMEN
Advances in DNA transposition technology have recently generated efficient tools for various types of functional genetic analyses. We demonstrate here the power of the bacteriophage Mu-derived in vitro DNA transposition system for modification and functional characterization of a complete bacterial virus genome. The linear double-stranded DNA genome of Escherichia coli bacteriophage PRD1 was studied by insertion mutagenesis with reporter mini-Mu transposons that were integrated in vitro into isolated genomic DNA. After introduction into bacterial cells by electroporation, recombinant transposon-containing virus clones were identified by autoradiography or visual blue-white screening employing alpha-complementation of E. coli beta-galactosidase. Additionally, a modified transposon with engineered NotI sites at both ends was used to introduce novel restriction sites into the phage genome. Analysis of the transposon integration sites in the genomes of viable recombinant phage generated a functional map, collectively indicating genes and genomic regions essential and nonessential for virus propagation. Moreover, promoterless transposons defined the direction of transcription within several insert-tolerant genomic regions. These strategies for the analysis of viral genomes are of a general nature and therefore may be applied to functional genomics studies in all prokaryotic and eukaryotic cell viruses.