element, e14. membrane protein encoded by a cryptic DNA bacteriophage T4 late gene expression is a The lit gene product which blocks

up-promotermutations in the cryptic DNAelemente14andthat the e14-encoded protein is localized in the inner mem-brane.MATERIALSANDMETHODSBacteria, phages, andplasmidconstructs. Table 1 summa-rizes the relevantfeatures oftheplasmidsandE. colistrainsused in our experiments. The phenotype ofplasmids con-taining subclones of the region of