RESUMO
Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.
Assuntos
Proteínas de Bactérias/genética , Genoma Bacteriano , Listeria monocytogenes/genética , Listeria/genética , Adaptação Fisiológica , Motivos de Aminoácidos , Bacillus subtilis/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/fisiologia , Composição de Bases , Proteínas de Transporte/química , Proteínas de Transporte/genética , Cromossomos Bacterianos/genética , DNA Bacteriano/química , DNA Bacteriano/genética , Transferência Genética Horizontal , Genes Bacterianos , Genômica , Listeria/química , Listeria/fisiologia , Listeria monocytogenes/química , Listeria monocytogenes/patogenicidade , Listeria monocytogenes/fisiologia , Proteínas de Membrana/química , Proteínas de Membrana/genética , Análise de Sequência de DNA , Staphylococcus aureus/genética , Fatores de Transcrição/química , Fatores de Transcrição/genética , Virulência/genéticaRESUMO
We present the sequence of a contiguous 2.63 Mb of DNA extending from the tip of the X chromosome of Drosophila melanogaster. Within this sequence, we predict 277 protein coding genes, of which 94 had been sequenced already in the course of studying the biology of their gene products, and examples of 12 different transposable elements. We show that an interval between bands 3A2 and 3C2, believed in the 1970s to show a correlation between the number of bands on the polytene chromosomes and the 20 genes identified by conventional genetics, is predicted to contain 45 genes from its DNA sequence. We have determined the insertion sites of P-elements from 111 mutant lines, about half of which are in a position likely to affect the expression of novel predicted genes, thus representing a resource for subsequent functional genomic analysis. We compare the European Drosophila Genome Project sequence with the corresponding part of the independently assembled and annotated Joint Sequence determined through "shotgun" sequencing. Discounting differences in the distribution of known transposable elements between the strains sequenced in the two projects, we detected three major sequence differences, two of which are probably explained by errors in assembly; the origin of the third major difference is unclear. In addition there are eight sequence gaps within the Joint Sequence. At least six of these eight gaps are likely to be sites of transposable elements; the other two are complex. Of the 275 genes in common to both projects, 60% are identical within 1% of their predicted amino-acid sequence and 31% show minor differences such as in choice of translation initiation or termination codons; the remaining 9% show major differences in interpretation.
Assuntos
Proteínas de Drosophila , Drosophila melanogaster/genética , Genes de Insetos/genética , Análise de Sequência de DNA/métodos , Cromossomo X/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Biologia Computacional , Elementos de DNA Transponíveis/genética , Proteínas de Ligação a DNA/genética , Feminino , Ordem dos Genes/genética , Masculino , Dados de Sequência Molecular , Mapeamento Físico do Cromossomo/métodos , Fatores de Transcrição/genéticaRESUMO
One of the rewards of having a Drosophila melanogaster whole-genome sequence will be the potential to understand the molecular bases for structural features of chromosomes that have been a long-standing puzzle. Analysis of 2.6 megabases of sequence from the tip of the X chromosome of Drosophila identifies 273 genes. Cloned DNAs from the characteristic bulbous structure at the tip of the X chromosome in the region of the broad complex display an unusual pattern of in situ hybridization. Sequence analysis revealed that this region comprises 154 kilobases of DNA flanked by 1.2-kilobases of inverted repeats, each composed of a 350-base pair satellite related element. Thus, some aspects of chromosome structure appear to be revealed directly within the DNA sequence itself.
