Bacteriophage T4, a new vector for the expression of cloned genes.

The amino-terminal portion of the T4 rIIB gene has been fused to the coding sequence of a truncated lacZ gene from Escherichia coli, giving rise to a fusion protein with beta-galactosidase activity. The 3192-bp rIIB-lacZ gene fusion was transferred into phage T4, and enzymatically active protein was produced after phage infection. T4 may be a useful expression vector in special circumstances, in particular for proteins whose accumulation in E. coli is limited by sensitivity to proteases.