Part:BBa_K255004

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

Network without any feedback and feedforward loop, present in pSB1A2 vector. BBa_K255004 represents a open loop system with constitutive expression of LacI and replication of plasmid copy. Both LacI and plasmid copy number are independent of IPTG concentration (inducer). 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

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 (fig.1).

Result

Since plasmid copy number was fixed and YFP was not under control of any IPTG inducible promoter, its expression was almost similar at the various IPTG conc. measured (fig.1).

Figure 1. Expression pattern of BBa_K255004

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_K255004 strain (fig.2)

Figure 2. Autofluorescence

Safety

Because this part is from commonly used elements in bacteria. No safety problem can be arised 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 1161
  
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]