Ribonuclease L (RNASEL)

RNase L is present in very minute quantities during the normal cell cycle. When interferon binds to cell receptors, it activates transcription of around 300 genes to bring about the antiviral state. Among the enzymes produced is RNase L, which is initially in an inactive form.

RNase L is part of the body's innate immune defense, namely the antiviral state of the cell. When a cell is in the antiviral state, it is highly resistant to viral attacks and is also ready to undergo apoptosis upon successful viral infection. Degradation of all RNA within the cell (which usually occurs with cessation of translation activity caused by protein kinase R is the cell's last stand against a virus before it attempts apoptosis.