Gene-engineered rigidification of membrane lipid enhance the cold inducibility of gene expression in Synechocystis

The exposure of Synechocystis sp.PCC 6803 (hereafter Synechocystis) cells to low temperature induces the expression of a specific set of genes that includes the desA, desD and desB genes for acyl-lipid desaturases. Previously we produced a series of mutants of Synechocystis in which the extent of unsaturation of fatty acids is modified in a step-wise manner. One of these mutants, desA-/desD-, synthesizes only a saturated C16 fatty acid and a monounsaturated C18 fatty acid regardless of the growth temperature, while the wild type synthesizes di-unsaturated and tri-unsaturated C18 fatty acids in addition to the monounsaturated C18 fatty acid (Tasaka et al, 1996). Thys system is suitable to examine the contribution of membrane fluidity/rigidity to the cold-inducible gene expression