title: Erratum.
abstract: Table 1 of the report "Reversible cleavage and ligation of hepatitis delta virus RNA" by H.-N. Wu and M. M. C. Lai (3 Feb., p. 652) contained an error. The religation percentage when the concentration of Mg(2+) in the cleavage reaction was 2.4 mM and the concentration of EDTA was 3.0 mM should have been 10. The correct table is printed below.