Table 1.
Transformation of Streptomyces lividans ZX7 using pSLA2-derived circular and linear plasmids
| Plasmids
|
Treatmenta
|
Transformation frequencyb
|
No. of transformant clones examinedc
|
|---|---|---|---|
| DraI-linearized pQC110 (from E. coli) | NT | 1 × 101 | 16 |
| λ exonuclease | 2 × 102 | 6 | |
| exonuclease III | 3 × 101 | 8 | |
| NaOH/HCl | 5 × 102 | 10 | |
| SacI-cleaved linear pQC26 (from ZX7) | NT | 8 × 101 | 8 |
| λ exonuclease | 1 × 103 | 19 | |
| exonuclease IIId | 9 × 101 | 8 | |
| NaOH/HCl | 5 × 103 | 35 |
a
NaOH/HCl treatment (see Materials and Methods). Partial digestion of DNA by λ exonuclease or exonuclease III. (NT) No treatment.
b
Relative transformation frequency obtained by comparing to transformation frequency of DraI-linearized pQC101 (5 × 103 transformants/μg DNA).
c
Linear plasmid DNA replicons were isolated from individual colonies by adding proteinase K/SDS or NaOH/SDS (see Materials and Methods). In all instances, 100% of clones examined contained long-palindromic DNA.
d
Treated with Klenow fragment of DNA polymerase I before exonuclease III treatment.