Identification of Streptococcus pneumoniae genes specifically induced in mouse lung tissues.
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.
Meng
Jiang-Ping
JP
Department of Laboratory Medicine, Chongqing University of Medical Sciences, Chongqing 400016, China.
Yin
Yi-Bing
YB
Zhang
Xue-Mei
XM
Huang
Yuan-Shuai
YS
Lan
Kai
K
Cui
Fang
F
Xu
Song-Xiao
SX
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
D001426:Bacterial Proteins; D005957:UTP-Glucose-1-Phosphate Uridylyltransferase; D001616:beta-Galactosidase