IS204: an insertion sequence from Nocardia asteroides (mexicana) YP21

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Insertion sequences (IS) are mobile genetic elements that play a significant role in shaping bacterial genomes.
• Understanding the diversity and characteristics of IS elements is crucial for comprehending bacterial evolution and adaptation.

Purpose of the Study:

• To characterize a newly identified insertion sequence, IS204, in Nocardia asteroides YP21.
• To investigate the structural features, potential function, and genomic distribution of IS204.

Main Methods:

• DNA sequencing and analysis of the insertion sequence IS204.
• Comparative sequence analysis of IS204 with known insertion sequences.
• Identification of open reading frames and prediction of protein function.
• Genomic Southern blotting or PCR to assess the copy number of IS204.

Main Results:

• IS204 is a 1452 bp insertion sequence with imperfect inverted repeats at its ends.
• IS204 shares high homology in its terminal inverted repeats with IS1096 from Mycobacterium smegmatis.
• An 8 bp target sequence duplication was observed at the insertion site.
• IS204 harbors an open reading frame encoding a putative transposase with similarity to those in IS1096 and Tn4652.
• At least nine copies of IS204 were detected in the Nocardia asteroides YP21 genome.
• IS204 demonstrated the ability to be inserted into a plasmid (pCY104::IS204) at a new site.

Conclusions:

• IS204 represents a novel mobile genetic element in Nocardia asteroides.
• The identified transposase suggests IS204 is a functional mobile element.
• The presence of multiple copies and potential for transposition indicates IS204 may contribute to genome plasticity in Nocardia asteroides.