Fig. 2. Expression of the arginine kinase gene in primmorphs is dependent on addition of silicic acid. Primmorphs were incubated in the presence (plus) or absence of silicic acid (minus) for 0-5 days. Then RNA was extracted, and identical amounts of total RNA were size-separated. After blot transfer, hybridization was performed using the probes for arginine kinase or the housekeeping gene ß-tubulin.