Bacteriophage P22 tail protein gene expression.

We have found that mutations which block bacteriophage P22 head assembly at or before the DNA packaging stage (1-, 2-, 3-, 5-, and 8-) cause up to a 20-fold increase in the amount of tail (gene 9) protein made during infection. This correlation seems strong enough to warrant consideration of a control mechanism in which the failure to package DNA per se causes a large increase in the synthesis of tail protein. Our results indicate that one of the repressors required for maintenance of lysogeny, the mnt gene product, may be partially responsible for this phenomenon.