Early: phage genes are transcr bed by host RNA polymerase 11.2 Lytic development is controlled by a AAA cascade Types of gene product Regul ator gene(s) RNA polymerase gma factor or antiteminat on factor Middle: early product causes transcript on of middle genes Figure 11. 4 Phage lytic development Regul ator gene(s) proceeds by a regulatory sigma fa ctor or antite minat on factor cascade, in which a gene Structural genes Replicat ion enzymes etc product at each stage is Late: middle product causes transcription of late genes needed for expression of the genes at the next stage d. Structural genes 请莘大 Phage componentsFigure 11.4 Phage lytic development proceeds by a regulatory cascade, in which a gene product at each stage is needed for expression of the genes at the next stage. 11.2 Lytic development is controlled by a cascade