[The study of insertion sequence IS2. II. Polarity effect of the mutant and DNA sequence analysis]

Insertion Sequence IS2 brought about polarity effect when it was inserted into a transcription. In study I, we found that the into polarity effects were different whether IS2 was inserted into the left side or into the right side. In this study, further research also showed that the polarity effects were very different when different IS2 was inserted into the left side. The analysis on IS2 DNA sequence showed that when the direction of IS2 ORF was the same as the transcription direction of the inserted transcription, known as a left insertion, the polarity effect was weaker. When the direction of IS2 ORF was opposite to the transcription direction of the inserted transcription, known as a right insertion, the polarity effect was stronger. When a stop codon was produced in IS2 due to base mutation, the polarity effect of a left insertion was increased.