Fig. 4. Northern transfer assay of developmentally regulated genes in a random integrant and an Ax2/gskA– mutant. Cells were developed on KK₂ agar and RNA was prepared from samples taken at 2 hour intervals over a period of 24 hours. The blot was hybridised with an ecmB- and a psA-specific gene probe. Detection of ecmA mRNA was by its cross-hybridisation with the ecmB probe. Re-probing with the constitutively expressed IG7 gene acts as a control for loading and transfer.