FIG. 7.

Proteasomal inhibition alters the nucleolar distribution of both rRNA and rRNA precursors in HeLa cells. In the control (DHSO) both 18S and 28S RNA FISH signals colocalize to a large extent with the B23 GFP-tagged construct (first rows in panels a and b). However, after proteasome inhibition (MG-132), both 18S rRNA and 28S rRNA signals exhibit a mixed pattern, with some areas colocalizing with B23 and others not (second rows in panels a and b). Note that the degree of mislocalization varied from cell to cell. The second row in panel a shows an example of a significant separation of the two signals, while the second row in panel b shows an example of a more modest effect. Scale bar, 5 μm.