Northern-blot analyses of H4,
Cdc2, and CycD3 steady-state mRNA levels
in wild-type seedlings (wt, s), wild-type calli (wt, c), and mutant
calli. Total RNA (50 μg) was separated in a denaturing formaldehyde
gel and, after blot transfer to a nylon filter, hybridized with
32P-labeled specific cDNA probes. Hybridization with a 25S
rDNA probe served as a control for loading.