Phage gene expression timing — Which protein sets are typically synthesized from late mRNA during a lytic infection?

Introduction / Context:Lytic phage infections proceed through an ordered transcriptional program: early genes for takeover and replication functions, and late genes for particle construction and release. Knowing which proteins appear from late mRNA clarifies phage biology and biotechnology applications.

Given Data / Assumptions:

• Late gene expression follows genome replication.
• Late mRNAs encode virion components and lysis machinery.
• Some late proteins assist assembly but are not retained in the mature virion.

Concept / Approach:From late mRNA, phages synthesize capsid and tail proteins (structural), assembly-helper proteins (scaffolding, chaperones), and lysis proteins (e.g., endolysins, holins) that mediate host cell rupture. Therefore, all listed categories are produced from late transcripts.

Step-by-Step Solution:

Verification / Alternative check:Well-characterized phages (e.g., T4) show this transcriptional order; late promoters drive structural and lysis genes.

Why Other Options Are Wrong:

• Picking only one subset ignores the full scope of late-phase products.

Common Pitfalls:Assuming lysis proteins are early; they are typically expressed late to time particle release.

Final Answer:All of the above