Tn916 transposition in Haemophilus influenzae Rd: preferential insertion into noncoding DNA.
Microb Comp Genomics
; 2(4): 313-21, 1997.
Article
em En
| MEDLINE
| ID: mdl-9689229
ABSTRACT
The availability of completely sequenced genomes has created an opportunity for high throughput mutational studies. Using the conjugative transposon Tn916, a pilot project was initiated to determine the efficiency of gene disruption in the first completely sequenced bacterium, Haemophilus influenzae Rd strain KW20. DNA was isolated from Tn916-mutagenized cells, and the point of transposon insertion was determined by inverse PCR, DNA sequencing, and mapping to the wild-type genome sequence. Analysis of the insertion sites at the nucleotide level demonstrated a biased pattern of insertion into regions rich in stretches of A's and T's. Although Tn916 integrated at multiple dispersed positions throughout the chromosome, 9 of 10 insertion events occurred in noncoding, intergenic DNA. It was determined that the intergenic DNA was over 5% more A + T-rich than that of protein coding sequences. This suggests that A + T-rich sequences similar to the Tn916 insertion site would be more likely to reside in the intergenic DNA. In an effort to identify other likely sites for transposon integration, a hidden Markov model of the consensus target insertion site was derived from the Tn916-H. influenzae junction fragments and searched against the entire genome. Eighty percent of the 30 highest-scoring predicted Tn916 target sites were from intergenic, nonprotein-coding regions of the genome. These data support the hypothesis that Tn916 has a marked preference for insertion into noncoding DNA for H. influenzae, suggesting that this mobile element has evolved to minimize disruption of host cell function on integration.
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Coleções:
01-internacional
Contexto em Saúde:
1_ASSA2030
/
3_ND
Base de dados:
MEDLINE
Assunto principal:
DNA Bacteriano
/
Elementos de DNA Transponíveis
/
Haemophilus influenzae
Tipo de estudo:
Health_economic_evaluation
/
Prognostic_studies
Idioma:
En
Revista:
Microb Comp Genomics
Ano de publicação:
1997
Tipo de documento:
Article