Northern blot analysis of SOL1 expression in termite
heads. Pseudergates (W) were exposed to JHA for 1 or 2 wk to induce
differentiation into the soldier caste (PS, JHA-induced presoldier; S,
soldier). Total RNAs from heads were resolved on denaturing agarose
gels, blotted, and probed. (a) 18S and 28S rRNA bands
stained with ethidium bromide indicate that approximately equal amounts
of RNA were loaded in each blot. (b) Hybridization with
the labeled SOL1 cDNA fragment. An arrow indicates the
SOL1 transcript (≈1 kb), which was strongly expressed
only in the soldier caste. Little or no expression was found in other
castes, even during the course of differentiation.