Nucleic Acids Research, 1982, Vol. 10, No. 13 3981-3993
© 1982
MOLECULAR BIOLOGY |
Insertion sites and the terminal nucleotide sequences of the Tn4 transposon
Biochemistry Program, Paul M.Althouse Laboratory, The Pennsylvania State University University Park, PA 16802, USA
*To whom correspondence should be addressed.
Received February 22, 1982. Revised May 11, 1982. Accepted May 21, 1982.
The nucleotide sequences at the ends of the Tn4 transposon (mercury, spectinomycin and sulfonamide resistance) have been determined. They are inverted repeated sequences of 38 nucleotides with three mismatched base pairs. These sequences are strongly homologous with the terminal sequences of Tn501 (mercury resistance) but less so with those of Tn3 (ampicillin resistance). The Tn4 transposon generates pentanucleotide direct repeat sequences at each of the insertion sites. These are A-T rich sequences analogous to those reported for most of the pentanucleotide members (Tn3, Tn1000, Tn501, Tn551, IS2) with the exception of Tn1721 and bacteriophage Mu. Among the three Tn4 insertion sites examined here, two of them occurred near a nonanucleotide sequence in perfect homology with part of the terminal inverted-repeat sequence of Tn4 and the third insertion occurred near a sequence of partial homology to one end of Tn4. All three insertions were in the same orientation such that IRb is proximal to its homologous sequence on the recipient DNA.