Assessment of Lysogenisity of Temperate Phages

Comparison of Repressibility of Promoter-like sequneces among Escherichia coli and its phages (P4 and lambda)

Shigehiko KANAYA
Yoshihiro KUDO

Faculty of Eng., Yamagata Univ.

By comparing, among Escherichia coli and 9 bacteriophages, repressibilities of occurrences of sigma-promoter consensus-like sequences in coding regions by means of an index (Ks) derived from x-statistic and principal conponents analysis (PCA), we have demonstrated that (1-1) the repressibility of the occurrences of the consensus-like sequences in the whole genome for E.coli is the highest of all the genomes, (1-2) the repressibilities for the two temperate phages (P4 and lambda) are similar to that for E.coli, and (2) the occcurrences of the consensus-like sequneces for other phages (T7, M13, fd, f1,IKe, G4, and phiX174). These results suggest that the repressibilty of the consensus-like sequences in genomic coding regions is an important factor to effectively E. coliordinate a web of gene control circuits, and assessment of similarities of phages to E.coli by the gene frequencies based on the two parameters (Ks and x) and PCA has made it possible to predict whether or not phage genomes can be coordinated with E.coli genome in transcription regulation.