CGSC Strain#: 6052
Strain Designation: R2D2      Source of Strain: J. Felton
Sex: F- Chromosomal Markers: ara-55, Δ(codB-lacI)3, asnB50::Tn5, gyrA91(NalR), relA1, spoT1, asnA31, rpoB318, thiE1
Strain Comments:

• The rpoB allele is described as a "cryptic" mutation.
• Δ(codB-lacI)3-- Shown by Ferrandez et al. 1997 to extend to mhpD
• Δ(codB-lacI)3-- is a deletion of the entire lac operon, from the strain Hfr 3000 X74 of Jacob. Refs. on extent of deletion: Sung et al.1987,J.Bact.169:2639; Gerdes et al.2001
• Δ(codB-lacI)3-- Shown by Durfee et al. to extend from codon 292 of yahG through mhpE
• spoT1-- In addition to the 6bp insertion, there is a C to T transition resulting in an H257Y substitution.
• asnA31-- Reported to be an amber mutation
• Δ(codB-lacI)3 was formerly called Δ(yahG-mhpE)
• Δ(codB-lacI)3 was formerly called X74
• Δ(codB-lacI)3 was formerly called DE(lac)6
• Δ(codB-lacI)3 was formerly called Δlac74
• Δ(codB-lacI)3 was formerly called Δ(lac)3
• thiE1 was formerly called thi-1
• = kanamycin resistant
• NalR = Nalidix.acidResist.

References:

• Felton, J, S Michaelis, A Wright 1980. Mutations in two unlinked genes are required to produce asparagine auxotrophy in Escherichia coli. J. Bacteriol. 142(1):221-8.