title: Identification of Streptococcus pneumoniae genes specifically induced in mouse lung tissues.
abstract: To identify Streptococcus pneumoniae genes expressed specifically during infections, a selection system based on the in vivo expression technology (IVET) was established. galU, which is critical for capsular polysaccharide biosynthesis, and lacZY encoding beta-galactosidase were employed as dual reporter genes to screen in-vivo-induced (ivi) genes of S. pneumoniae. The galU-deficient mutant of S. pneumoniae is incapable of utilizing galactose, thus failing to synthesize capsular polysaccharide, and therefore loses its ability to survive in the host. A promoter-trap library was constructed in S. pneumoniae, which was used to infect BALB/c mice in an intranostril model. Those strains recovered from lung tissue of mice and exhibiting a white colony phenotype on tryptic soy agar containing X-gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside) were collected and identificated. A total of 15 unique sequences were obtained through in vivo screening. The ivi genes of S. pneumoniae are involved in many processes, such as colonization and adherence, energy metabolism, nutrient substance transport, transcription regulation, DNA metabolism, and cell wall synthesis. There are some hypothetical proteins whose functions are not clear. This novel IVET is a useful tool for identifying ivi genes in S. pneumoniae.
authors.affiliation: Department of Laboratory Medicine, Chongqing University of Medical Sciences, Chongqing 400016, China.
authors.forename: Jiang-Ping
authors.initials: JP
authors.lastname: Meng
authors.forename: Yi-Bing
authors.initials: YB
authors.lastname: Yin
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Zhang
authors.forename: Yuan-Shuai
authors.initials: YS
authors.lastname: Huang
authors.forename: Kai
authors.initials: K
authors.lastname: Lan
authors.forename: Fang
authors.initials: F
authors.lastname: Cui
authors.forename: Song-Xiao
authors.initials: SX
authors.lastname: Xu
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D017930:Genes, Reporter; D005822:Genetic Vectors; D015698:Genomic Library; D008168:Lung / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011008:Pneumococcal Infections / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000472:pathogenicity; D014169:Transformation, Bacterial; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase / Q000235:genetics / Q000378:metabolism; D014774:Virulence; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase; D001616:beta-Galactosidase