Characterization of IS1515, a Functional Insertion Sequence in Streptococcus pneumoniae
AUTOR(ES)
Muñoz, Rosario
FONTE
American Society for Microbiology
RESUMO
We describe the characterization of a new insertion sequence, IS1515, identified in the genome of Streptococcus pneumoniae I41R, an unencapsulated mutant isolated many years ago (R. Austrian, H. P. Bernheimer, E. E. B. Smith, and G. T. Mills, J. Exp. Med. 110:585–602, 1959). A copy of this element located in the cap1EI41R gene was sequenced. The 871-bp-long IS1515 element possesses 12-bp perfect inverted repeats and generates a 3-bp target duplication upon insertion. The IS encodes a protein of 271 amino acid residues similar to the putative transposases of other insertion sequences, namely IS1381 from S. pneumoniae, ISL2 from Lactobacillus helveticus, IS702 from the cyanobacterium Calothrix sp. strain PCC 7601, and IS112 from Streptomyces albus G. IS1515 appears to be present in the genome of most type 1 pneumococci in a maximum of 13 copies, although it has also been found in the chromosome of pneumococcal isolates belonging to other serotypes. We have found that the unencapsulated phenotype of strain I41R is the result of both the presence of an IS1515 copy and a frameshift mutation in the cap1EI41R gene. Precise excision of the IS was observed in the type 1 encapsulated transformants isolated in experiments designed to repair the frameshift. These results reveal that IS1515 behaves quite differently from other previously described pneumococcal insertion sequences. Several copies of IS1515 were also able to excise and move to another locations in the chromosome of S. pneumoniae. To our knowledge, this is the first report of a functional IS in pneumococcus.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=107034Documentos Relacionados
- Identification and characterization of IS1381, a new insertion sequence in Streptococcus pneumoniae.
- Isolation, characterization, and nucleotide sequence of IS1202, an insertion sequence of Streptococcus pneumoniae.
- Insertion-Duplication Mutagenesis in Streptococcus pneumoniae: Targeting Fragment Length Is a Critical Parameter in Use as a Random Insertion Tool
- Characterization of IS905, a new multicopy insertion sequence identified in lactococci.
- Genetic Analysis and Functional Characterization of the Streptococcus pneumoniae vic Operon