Kit 11 Streptomycin Point Mutants in S. typhimurium
One method to locate a gene on the chromosome if it has a selectable phenotype is to transfer it by conjugation and look for linkage to known genes. The strain with the selectable marker e.g., Tn10 with Tet-res can be made Flac(+) by conjugation and selection for Lac(+); this strain can be mated as donor to a strain with a known auxotrophic mutation (e.g., trp) with selection for Tet-res (from the donor chromosome) and Str-res (counter-selection against the donor cell), and the linkage between Tet-res and the Trp(- )phenotype can be determined. A set of about 40 Str-res strains, each with a single auxotrophic mutation at locations around the chromosome, has been constructed, as listed below.
Min Strain # Gene Auxotrophy 0 SA3661 thrA threonine 2 SA3646 pyrA uracil and arginine 3 SA3662 leuB leucine 5 SA3630 panB pantothenic acid 7 SA3631 proB proline 8.5 SA3632 proC proline 12 SA3663 purE adenine 14 SA320 lip lipoic acid 18.5 SA3633 bio biotin 21 SA3655 pyrD uracil 23 SA3658 pyrC uracil 25 SA3634 purB adenine 28 SA3635 aroD tyrosine, tryptophan, phenylalanine 33.5 SA3636 pyrF uracil 34 SA3637 trpC tryptophan 42 SA3647 hisH histidine 44 SA3648 metG methionine 47 SA3638 purF adenine 50 SA3649 cysA cysteine 51 SA3656 purC adenine 54 SA3639 glyA glycine 55 SA3657 tyrA tyrosine 60 SA3650 cysC cysteine 61 SA3640 argA arginine 68 SA3651 argG arginine 71 SA3667 aroE tyrosine, tryptophan, phenylalanine 72 SA3664 argD arginine, proline 73 SA3668 aroB tyrosine, tryptophan, phenylalanine 79 SA3641 cysE cysteine 79.5 SA3840 pyrE uracil 83 SA3653 ilvE isoleucine, valine 84 SA3645 metE methionine 87.5 SA3642 metB methionine 88 SA3654 argE arginine 89 SA3665 purD adenine 96 SA3666 purA adenine 97 SA3660 argI arginine 98 SA3643 pyrB uracil 99.5 SA3644 serB serine