Programmed Escherichia coli cell lysis by expression of cloned T4 phage lysis genes.

Self-disruptive Escherichia coli that produces foreign target protein was developed. E. coli was co-transformed with two vector plasmids, a target gene expression vector and a lysis gene expression vector. The lytic protein was produced after the expression of the target gene, resulting in simplification of the cell disruption process. In this study, the expression of cloned T4 phage gene e or t was used for the disruption of E. coli that produced beta-glucuronidase (GUS) as a model target protein. The expression of gene e did not lead to prompt cell disruption but weakened the cell wall. Resuspension with deionized water facilitated cell lysis, and GUS activity was observed in the resuspended liquid. Expression of gene e at mid logarithmic growth phase was the optimal induction period for GUS production and release. On the other hand, the expression of gene t induced immediate cell lysis, and intracellular GUS was released to the culture medium. Maximum GUS production was obtained when gene t was induced at late logarithmic growth phase.