Erratum

The caption for figure 1 (p. 1497) of the report "Transformation by v-sis occurs by an internal autoactivation mechanism" by B. E. Bejcek et al. (29 Sept., p. 1496) was inadvertently not printed. The caption should have read, "Fig. 1. (A) Plasmid pSEB3 (B) Mutations used."