Fig. 2. Developmental time course of CblA expression. Cells were allowed to develop for the indicated times (in hours) and stages (s, slug; MC, mid-culminants; C, culminants) on filters. The times in B are equivalent to the following stages: 6 hours, streaming; 10 hours, tight aggregates; 12 hours, tipped aggregates and first fingers; and 14 hours, slugs. Cells were analysed for (A) CblA RNA by RT-PCR and (B) CblA protein by western transfer. The loading control in A is Ig7, a constitutively expressed RNA. Loading in the western transfer was monitored by total protein staining and was approximately equal in all lanes.