Figure 6.

Some mutant U3 snoRNAs can compete for wild-type U3 nucleolar localization. One-half (0.46 ng/oocyte) of the usual amount of fluorescein-labeled wild-type U3 snoRNA was coinjected with a 100-fold molar excess of various unlabeled RNAs as competitor. No competition is seen by U2 snRNA or U3 Box C or U3 Box D mutants, partial competition is seen by the U3 Box B mutant, and full competition is seen by the other samples. PC, DAPI, and FL as in Figure 1. Lampbrush chromosomes are seen in the PC and DAPI panels of the U3 Box A+ and U3 Box C competitor samples. Bar, 10 μm.