Question

The order of the genes in bacteriopage alpha is: A B C D E att int xis N CI O P Q S R

Given the bacterial attachment site , att, is between gal and bio in the bacterial chromosome, what is the prophage gene order?

A mutant phage is found to have the reverse gene order in the prophage as in the wildtype prophage. What does this say about the orentation of the att site in regard to the termini of the phage chromosome?

Answer 1

The att, is between gal and bio in the bacterial prophage. The phage (attP) is designated as 'POP’and bacterial is designated as BOB’, and the prophage (attB) att sites are designated BOP’ (attL) and POB’ (attR).The prophage gene order is gal BOP’ (attL)A B C D E att int xis N CI O P Q S RPOB’ bio (attR).

A mutant phage is found to have the reverse gene order in the prophage as in the wildtype prophage. It causes excision of the prophase. It will be 'BOB' and 'POP' sites. The phage enzyme integrase and a phage protein excisionase is required for reverses the integration process.