Cloning the BST(VI) retriction- modification system in Escherichia coli

Enrique González and Claudio Vásquez Laboratorio de Biología Molecular, Departamento de Ciencias Biológicas, Universidad de Talca, Casilla 747, Talca, Chile.A standard DNA modification methyltransferase (MTase) selection protocol was followed to clone the BstVI restriction and modification system from Bacillus stearothermophilus in Escherichia coli. Both genes were contained in a 4.4-kb EcoRI fragment from B. stearothermophilus V chromosomal DNA. The heterologous expression of these genes did not depend on their orientation in the vector, suggesting that the genes are expressed in E. coli under the control of promoters located on the cloned fragment. Subcloning experiments demonstrated that the bstVIR gene was expressed in the absence of its cognate MTase.RESTRICTION ENDONUCLEASE; MODIFICATION METHYLTRANSFERASE; BACILLUS-STEAROTHERMOPHILUS; HETEROLOGOUS GENE EXPRESSION; RECOMBINANT DN