Part:BBa_K255001

pLac.lacI-cfp(fusion).terminator.ptet.yfp.teminator

It has dual negative feedback loop one on the plasmid copy number and second on the LacI expression. This network is present in IPTG inducible plasmid,pSB2K3. Both LacI and plasmid copy number are dependent on IPTG concentration (inducer). The copy number is characterized by YFP while LacI is characterized by LacI-CFP fusion protein.

Characterization

YFP was measured using FACS analysis. Illustrative FACS results are given below: The mean, variance and standard error were noted for difference strains and at different IPTG concentration. The FACS results are shown for varying IPTG concentrations varying from 0um to 500um.

Result

The YFP Expression increased around 10 folds from 0 to 100 μM of IPTG Conc and thereafter its value was almost constant to 200 and 500 μM of IPTG conc (fig.1).

Figure 1. Expression of BBa_K255001 in lacI deleted E.coli strain

After this the expression profile of YFP between 0 and 100 μM was measured(fig.2).

Figure 2. Expression of BBa_K255001 in lacI deleted E.coli strain

As a control, FACS was done with host strain to quantitate the autofluorescence. It was observed that cells are showing autofluorescence but its intensity is very less than our BBa_K255001 strain (fig.3).

Figure 3. Autofluorescence

Safety

Because this part is from commonly used elements in bacteria. No safety problem can be arisen by this part.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  INCOMPATIBLE WITH RFC[21]

  Illegal XhoI site found at 1162
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]