Escherichia coli Insertion Sequence IS150: Transposition via Circular and Linear Intermediates

AUTOR(ES)

Haas, Markus

FONTE

American Society for Microbiology

RESUMO

IS150, a member of the widespread IS3 family, contains two consecutive out-of-phase open reading frames, orfA and orfB, that partially overlap. These open reading frames encode three proteins, InsA, InsB, and the InsAB protein, which is jointly encoded by both open reading frames by means of programmed translational frameshifting. We demonstrate that the InsAB protein represents the IS150 element's transposase. In vivo, the wild-type IS150 element generates circular excision products and linear IS150 molecules. Circular and linear species have previously been detected with mutant derivatives of other members of the IS3 family. Our finding supports the assumption that these products represent true transposition intermediates of members of this family. Analysis of the molecular nature of these two species suggested that the circular forms are precursors of the linear molecules. Elimination of InsA synthesis within the otherwise intact element led to accumulation of large amounts of the linear species, indicating that the primary role of InsA may be to prevent abortive production of the linear species and to couple generation of these species to productive insertion events.

Documentos Relacionados

• IS150: distribution, nucleotide sequence and phylogenetic relationships of a new E. coli insertion element.
• IS861, a group B streptococcal insertion sequence related to IS150 and IS3 of Escherichia coli.
• IS231A from Bacillus thuringiensis is functional in Escherichia coli: transposition and insertion specificity.
• Site-specific transposition of insertion sequence IS630.
• Fate of donor insertion sequence IS1 during transposition.