Fig. 2. Distribution of dmtA mRNA in developing structures of strain Ax2. This mRNA encodes the methyltransferase catalysing the last step in DIF-1 biosynthesis and is clearly prespore specific from the time when a specific signal can be first detected. (A) Mound just before tip formation; (B) tipped mound; (C,D) slugs (a graded distribution of dmtA mRNA is apparent in the prespore zone); (E) Mexican hat; (F) early culminant.