Part:BBa_K1185000

L-form switch BioBrick

This BioBrick can be used as a switch to enable the model Gram-positive bacteria Bacillus subtilis to switch between cell-walled rod form and wall-less L-form. The BioBrick contains homologous regions to the pbpB and murE genes to allow integration into the chromosome of B. subtilis via homologous recombination. Within the BioBrick there is a xylose-controlled promoter PxylR. This promoter is upstream of the murE coding sequence when integrated into the chromosome of B. subtilis, placing murE expression under the control of PxylR. The murE gene is responsible for the synthesis of enzymes involved in production of peptidoglycan synthesis. Disruption of this pathway can be utilised to down-regulate production of the cell wall.

After integration of the BioBrick, the expression of murE is controlled by the presence, or absence, of xylose (via the PxylR promoter). When xylose is present, murE is expressed and functional cell wall is produced. When xylose is not present the cell wall is no longer produced and cells can transition to the cell wall-less L-form phenotype.

The BioBrick also contains a cat gene, conferring chloramphenicol resistance. This can be used to select for transformants in rod form.

Details on the transformation of this BioBrick into B. subtilis, selection for transformants and the culturing of L-forms can be found on our [http://2013.igem.org/Team:Newcastle wiki].

This BioBrick only functions in enabling switching between walled cells and wall-deficient L-forms in B. subtilis.