Inside human cells, the coronavirus faces an army of enzymes that can destroy its RNA genome. These enzymes, called nucleases, are constantly patrolling the cell, searching for and destroying foreign nucleic acids.

The coronavirus has evolved a number of ways to evade these nucleases. One way is to hide its RNA genome inside a protective protein coat. Another way is to produce proteins that inhibit the activity of nucleases.

However, the human cell has also evolved a number of ways to combat these viral defenses. One way is to produce nucleases that are specifically designed to target the coronavirus RNA genome. Another way is to produce proteins that can activate the nucleases and overcome the viral inhibitors.

The battle between the coronavirus and the human cell is a constant one. The virus is constantly trying to evade the cell's defenses, while the cell is constantly trying to destroy the virus. The outcome of this battle will determine whether the person infected with the coronavirus develops COVID-19.

Here are some of the host-cell enzymes that have been shown to play a role in combating the coronavirus:

* RNase L: This enzyme is activated by the viral protein dsRNA, which is produced when the virus replicates. RNase L then destroys the viral RNA genome.

* RNAse H: This enzyme is involved in the degradation of viral mRNA.

* Proteases: These enzymes break down viral proteins, including the proteins that inhibit the activity of nucleases.

* Kinases: These enzymes phosphorylate viral proteins, which can activate the nucleases and overcome the viral inhibitors.

These are just a few of the many host-cell enzymes that are involved in combating the coronavirus. The research into these enzymes is ongoing, and it is hoped that this research will lead to the development of new treatments for COVID-19.