TABLE 3.
Mapping S. typhi insertion mutations in S. typhimurium
| Original S. typhi straina | Relevant phenotype | Mud-P22 lysate scoring positiveb | Map position (cs) in S. typhimuriumc | Putative locus affected | Inferred map position (cs) in S. typhid |
|---|---|---|---|---|---|
| TyT1009 | Met− | zgf-3716::MudP | 66–70 | metC | 93–97 |
| TyT1015 | Arg− | cysHIJ1574::MudQ | 64–65 | argA | 99–1 |
| TyT1020 | Ilv− | metE2131::MudP | 85–86 | ilv operon | 88–90 |
| TyT1031 | Leu− | nadC218::MudQ | 1–3 | leu operon | 58–60 |
| TyT1041 | Phe− | purG2149::MudP | 56–59 | pheA | 4–7 |
| NN19 | Chlrf | nadA219::MudP | 17–19 | modCe | 17–19 |
| JJ3 | Chlr | nadA219::MudP | 17–19 | moaAe | 17–19 |
| DD46 | Chlr | zgf-1716::MudQ | 67–69 | uxaC | 95–97 |
Strains are derivatives of S. typhi Ty2. They belong to a collection of MudJ insertion mutants obtained following the protocol of Hughes and Roth (10). Chromosomal DNA from these strains was prepared according to a previously described method (1) and was used to transform cells of strain MA5383 (metA22 metE551 galE496 rpsL120 xyl-104 Δ[Fels2] H1-b H2-e,n,x nml hsdL6 hsdSA29 recD543::Tn10dTc mutS171::Tn10dCm), selecting for Kanr. Insertions were then transferred to strain LT2 by P22-mediated transduction and were mapped, with prototrophy scored as previously described (2). For MudJ insertions conferring phenotypes other than auxotrophies, a Tetr marker was introduced within the MudJ element. This was done by using a P22 lysate prepared from a strain carrying lacZ::Tn10 to transduce the different MudJ-carrying strains, selecting for Tetr. Lac− Tetr transductants were purified and the Tn10 element was mapped on Tets selection medium as previously described (2, 15).
Mud-P22 lysates, enriched for selected regions of the S. typhimurium chromosome, were prepared from a collection of 54 lysogenic strains and were used for transduction as previously described (21). Typically, overlapping lysates would concomitantly score positive in the assay (Fig. 1). Only the lysate producing the strongest signal in each transduction series is shown here.
Centisomes (cs) are from edition VIII of the S. typhimurium genetic map (19). Intervals are those of the two strongest phage signals observed.
Centisomes (cs) were calculated from Table 2 of reference 11, taking 4,780 kb as the size of the S. typhi chromosome.
Assignments were made on the basis of phenotypic characterization of mutants (3) and the relative strengths of the second strongest transduction result in each case.
Chl, chlorate.