Fig. 2. Selective expression of gamone 1 in B. japonicum cells. (A) The transcriptional levels of the gamone 1 gene were examined by northern analysis using probe 2. Total RNA was extracted from mating type I (I) and II (II) cells and was separated by electrophoresis (6 µg/lane). Gamone 1 mRNA (about 1000 bases) was detected only in samples prepared from mating type I cells. The graph shows the relative amounts of gamone 1 mRNA with respect to that of rRNA calculated from the results of the northern hybridisation above. (B) The secreted mature gamone 1 protein was detected by SDS-PAGE and silver staining. (C) The biological activity of secreted mature gamone 1 is represented as the index of pair formation (black bar) and in units (cross-hatched bar).