Virology T7 and Lambda

• Naked icosahedral
• T7 has a short tail
• Lambda has a long flexible tail

• 1. Adsorption (attachment through tail fiber)
• 2. Injection of DNA
• 3. Trx/Tln early genes
• 4. Replication
• 5. Trx/Tnl late genes
• 6. Assembly in cytoplas
• 7. Release by lysis

Class 1 (early), 2 (rep.), and 3 (structure/assembly) which are clustered by function and timing

• Injection
• bacterial RNA pol recognition
• Spooling (coupled to trx)
• At TE sequence bacterial pol releases mRNA and viral pol takes over

• Lytic
• Lysogenic

The switch from lysogeny to lytic modes and is controlled by CL (represses Pr and Pl) and CRO (represses Prm to cont turn down Pr and Pl)