Abstract
Changes in the phage protein patterns obtained by gel electrophoresis of extracts from phage S13 and phiX174 infection of rifampin-resistant hosts suggest that the beta subunit of ribonucleic acid polymerase of Escherichia coli has a function in the recognition of promoter or terminator sites or both. The altered protein patterns also provide information on the location of some ribonucleic acid polymerase recognition signals in S13 deoxyribonucleic acid. There is a promoter site before gene A, which lies either in gene H or between H and A. There is evidence for a promotor between genes C and D or in gene C. There is either a terminator or a promoter somewhere between the end of gene D and the beginning of gene F.