| Types || |
| Roles |
| Sequences || BBa_K143033_sequence (Version 1)|
DescriptionLacI is a regulatory protein responsible for the repression of many catabolite genes. Transcription is regulated by proteins which bind operator sequences around the transcription start site. These proteins can positively affect transcription (activators) or negatively affect transcription (reppresors). Some repressor proteins can be inactivted however by addition of an inducer, such as IPTG or certain sugars.
LacI if the regulator protein for the lactose operon in E.coli and the hyper-spank protein of B. subtilis#1(BBaK143015) and is responsible for ensuring that in the absence of lactose (or IPTG) that there is no expression trough these promoter. LacI is not endogenous to B. subtilis, so LacI will need to be expressed in the host in order for the hyper-spank promoter to be regulated. In the presence of IPTG or lactose, the LacI tetramer is unable to bind DNA and so transcription resumes.
This version of LacI lacks a Lva degradation tag and has a small(3 amino acid) N-terminal deletion relative to the current registry LacI (BBa_C0012 and is derivatives. The N-terminal deletion appears to be common to most of the LacI genes used in conjunction with B. subtilis though both forms are found in E.coli (in differing strains).
LacI was used in conjunction with the Hyper-spank promoter (BBa_K143015) and acted as an input adaptor for a Polymerases per second (POPS) output
NotesLacI was located in the sequence of the B. subtilis shuttle vector pDR111. This version of LacI lacks a Ltva degradation sequence and has a small N-terminal deletion that is observed in many LacI used in studies on B.subtilis. In particular, this LacI protein is used in pDR111 to regulate expression of the inducible Phyper-spank protein (BBa_K143015) (also used in the pDR111 vector). The BioBrick prefix and suffix were applied to the gene
SourceThe LacI gene was cloned fromB. subtilis shuttle vector pDR111 using Pfu DNA polymerase PCR