Bacterial toxin RNase RnlA (IPR045837). RnlA (RNase LS) and LsoA are type II TA systems that are involved in the defense of bacteriophages. Following infection with bacteriophage T4, bacteriophage T4 activates RnlA and LsoA, revealing their endoribonuclease activity. RnlA is a stable toxin that inhibits cell growth and swiftly degrades T4 late mRNA to prevent its expression. The activity of the unstable antitoxin RnlB neutralizes RnlA.