Part:BBa_K801033

LexA DNA binding protein

LexA DNA binding protein, improved version of BBa_K105005 to allow N- and C-terminal protein fusions using RFC25 pre- and suffix.

LexA is a prokaryotic transcription factor which can be used also in eukaryotic systems to binds selectively to LexA operator sequence, which can be fused to the TATA boxes of a minimal eukaryotic promoter. If used in eukaryotic systems it is nescessary to fuse a nuclear localization signal (BBa_K801030, SV40 nuclear localization sequence) to this part to allow nuclear translocation. Of course there is no NLS nescessary in procaryotic systems.

If you want to fuse a protein domain to the N-terminus of this part and also want to ensure independent folding of protein domains you might want to use a protein linker in the N-terminus of this part. A composite parts already exists in which a 20 amino acids long linker is fused to the N-terminus of this part (BBa_K801036).

Background

Principle of light-dependent switching of gene-expression.

In contrast to the GAL4 based light-switchable promoter system there is no need for KO of GAL4/GAL80 genes in yeast with a LexA based light-switchable promoter system. The difference is that we use LexA, a prokaryotic DNA binding protein, for the DNA binding part of our light-switchable promoter system, instead of GAL4DBD. LexA does not interfere with the endogenous yeast metabolism and signaling system because it only recognizes a special prokaryotic DNA sequence, the so-called LexA operator (=LexA binding site). LexA binding sites can be used upstream of a minimal promoter (=TATA box) to be utilized as a cis-acting regulatory element. In this case the genes, which we want to control by light, have to be cloned downstream of a synthetic promoter containing a minimal promoter, preceded by multiple LexA binding sites

Usage and Biology

Sequence and Features

Assembly Compatibility:

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

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• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]