CGSC Strain#: 750
Strain Designation: AB750      Source of Strain: DeWitt
Sex: Hfr    Point of Origin#:    Map Position: Chromosomal Markers: fhuA24, lacY40, glnV44(AS), galK2(Oc), malB5::Sfa(att)
Strain Comments:

• F is integrated in malB locus ( sfa-3).
• lacY40-- When lacY40 and lac ? appear in a genotype, it is meant to indicate that lacY40 has become more stable due to a second mutation, perhaps in lac occurring in W3828.
• galK2(Oc)-- is a GAA(glu) to TAA(ochre) mutation, residue 134. Oller et al.1993. Apparently non-suppressible, since all revertants found were at the ochre site.
• malB5::Sfa(att)-- sfa-3 is a sex factor-attachment-site in malB. When infected with F, this strain gives rise to an Hfr with the point of origin of Richter's Hfr3 (in malB).
• galK2(Oc) was formerly called gal₂
• glnV44(AS) was formerly called supE44
• glnV44(AS) was formerly called su⁺_II
• AS = amber(UAG) suppressor
• Oc = ochre(UAA) mutation

References:

• Dewitt, SK, EA Adelberg 1962. The Occurrence of a Genetic Transposition in a Strain of Escherichia Coli. Genetics 47(5):577-85.
• PITTARD, J, JS LOUTIT, EA ADELBERG 1963. GENE TRANSFER BY F' STRAINS OF ESCHERICHIA COLI K-12. I. DELAY IN INITIATION OF CHROMOSOME TRANSFER. J. Bacteriol. 85:1394-401.