ISMh2, a novel insertion sequence-like element associated with nifA from Mesorhizobium huakuii

Sequence analysis of the nifA gene, including its 5' flanking region, of Me sorhizobium huakuii revealed the presence of a novel IS-like element called ISMh2. It is 828 bp in length and possesses two imperfect terminal inverte d repeats of 14 bp with only one mismatch. The putative transposase encoded by ISMh2 is composed of 204 amino acids. In comparison with other insertio n sequences ISMh2 Likely belongs to the IS6 family. Multiple copies of ISMh 2 were detected in the genome of M. huakuii 159 by Southern hybridization. RT-PCR analysis showed that nifA and ISMh2 cotranscribed. Attempts to detec t the transposition ability of ISMh2 were unsuccessful. (C) 2001 Academic P ress.