Part:BBa_K255003

pLac.lacI-cfp(fusion).terminator.pTet.yfp.terminator

Network with a negative feedback loop, present in pSB1A2 vector. Expression of lacI is under auto negative regulation. Here the copy number of the plasmid is fixed.The copy number is characterized by YFP while LacI is characterized by LacI-CFP fusion protein. YFP was measured using FACS and the distribution obtained was independent of IPTG. Beta-galactosidase was also measured at various lactose concentration to characterize the expression of gene in the host genome. Further the growth of the transformant was also characterized at different lactose concentrations.

Characterization

Steady state concentration of YFP was measured using FACS. 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 was found to be nearly same at all the different concentrations of IPTG(fig.1).

Figure 1.Expression of BBa_K255003 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_K255003 strain (fig.2)

Figure 2. 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]