Figure 3.
Condensin mutants show loss of tRNA gene and pre-tRNA nucleolar localization. Fluorescence in situ hybridization to the tRNALeu genes and the early precursor tRNAs (pre-tRNALeu) in wild-type cells shows the genes and their transcripts clustered at the nucleolus, as described previously (Bertrand et al. 1998; Kendall et al. 2000; Thompson et al. 2003; L. Wang et al. 2005). However, mutations in condensin subunits change the patterns of tRNA gene clusters. In some cases, the tRNA genes disperse (smc2-8, smc4-1, ycs4-1) such that the fluorescent signal is no longer detectable above the background, and in other cases, they mislocalize outside of the nucleolus (ycg1-2, brn1-9). Pre-tRNA positions are also altered, in some cases localizing near the nuclear periphery (ycs4-1, brn1-9) and in others diffusely in the nucleoplasm (smc2-8, smc4-1, ycg1-2).