Answer to Question #265321 in Microbiology for sparrow

Question

Which promoter initiates which life cycle (lysogenic & Lytic)? Mention both types of promoters and their characteristics.

Answer 1

Lysogenic cycle.

The critical point in establishing lysogeny is the synthesis of the lambda repressors encoded by the cl gene. This gene has two promoters -P$_E$ for establishing lysogeny and $P_M$ for maintaining lysogeny.

Lytic cycle

During lytic cycle, phage gene transcription is initiated from three promoters:

P1 and P2 which controls the expression for early phage genes involved in genome replication and P3 which controls the expression of the late genes responsible for vision maturation and host lysis.