Naked MudJ Revealed

Using Solexa methodology, I recently sequenced strain SMP1666 (from Sophie Maisnier-Patin), containing 3 copies of MudJ. One had lost the infamous trpB-proximal stem-loop structure1,2, and the other two were pristine — one hesitates to say “wild type” as the lollypop structure was itself an artifact of the original construction out of a MudI background3. The complete MudJ sequence can be found here. The big surprise is the cynX & cynS genes between lac and the Tn5 drug-resistance cassette.

1.J.Zieg & R.Kolter (1989) “The right end of MudI(Ap,lac)” Arch.Microbiol. 153 1-6
2.W.Metcalf, P.Steed & B.Wanner (1990) “Identification of Phosphate Starvation-Inducible Genes in Escherichia coli K-12 by DNA Sequence Analysis of psi::lacZ(Mu dl) Transcriptional Fusions” J.Bacteriol. 172 3191-3200
3.B.Castilho, P.Olfson & M.Casadaban (1984) “Plasmid insertion mutagenesis and lac gene fusion with mini-mu bacteriophage transposons” J.Bacteriol. 158 488-495

-- Eric Kofoid

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