Which virus promotes apoptosis?

While the provided reference doesn't explicitly name a virus that promotes apoptosis, it highlights several viruses that encode products that influence or prevent apoptosis. The reference focuses on mechanisms of viral interference with cell death rather than viruses that directly induce it. Therefore, based on the information provided, it's more accurate to discuss viruses impacting apoptosis rather than directly promoting it. However, we can infer information about how some viruses can indirectly promote it.

Viral Influence on Apoptosis: A Closer Look

Instead of viruses directly "promoting" apoptosis, many viruses have mechanisms to inhibit or modulate the process. This is often because apoptosis is a host defense mechanism that viruses need to circumvent to replicate successfully. Here are examples based on the provided reference:

• Adenovirus:

  • Encodes E1B-19K, which functions similarly to Bcl-2.
  • E1B-19K can influence mitochondrial-induced cell death.
  • It also modulates apoptosis mediated through Fas and TNFR-1.

• Cowpox virus:

  • Encodes crmA, which prevents caspase activation.

• Insect baculovirus:

  • Encodes p35, which also prevents caspase activation.

How Viruses Indirectly Promote Apoptosis

Although the reference mainly talks about inhibiting apoptosis, we can still explore how they indirectly lead to the process:

• Stress Induced by Viral Replication: The intense replication cycle of viruses within a host cell can cause significant stress. This stress can trigger cellular responses that lead to apoptosis if not effectively suppressed by the virus. For example, the massive production of viral proteins and genetic material can overwhelm the cell's internal systems.

• Immune Response: In some cases, the host's immune system's response to the viral infection can indirectly trigger apoptosis in infected cells. For example, cytotoxic T lymphocytes (CTLs) can induce apoptosis of virus-infected cells. While not directly the virus's doing, the virus is the root cause.

• Dysregulation of Cellular Processes: Viruses can hijack cellular machinery, leading to a dysregulation of normal cellular functions. In cases where cellular damage is severe, or where the normal apoptotic pathways are not properly inhibited, programmed cell death may proceed.

Table of Viral Products Affecting Apoptosis

Summary

Based on the provided information, the reference primarily focuses on viral products that inhibit apoptosis rather than directly promoting it. However, indirect mechanisms due to viral activity may eventually induce apoptosis. Some of these indirect ways include viral replication stress, immune response, and disruption of normal cell functions.