FIG. 1.

Induction and repression of centrin RNAi. A. Schematic presentation of the NIT1-centrin-IR construct. The putative start of transcription is based on data available at http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?val=AF203033.1. B-E. Control and nitRNAi1 cells were maintained in either NH₄Cl medium (NH₄Cl) or NH₄Cl-free medium (KNO₃) or returned to NH₄Cl medium after being maintained in ammonium-free medium for several weeks (KNO₃ → NH₄Cl). B. Indirect immunofluorescence for centrin. Arrowhead, dCF; arrow, NBBC. Bar, 5 μm. C. The % of cells with wild-type centrin fibers for control and nitRNAi1 cells. D. Northern blot probed with genomic [³²P]ATP-labeled DNA encoding centrin or, as a loading control, a biotin-labeled probe to Cb2 (13); 25 μg of total RNA was loaded per lane. E. Western blot of detergent-extracted control and nitRNAi1 cells. The lower part of the membrane was stained with anticentrin, and the upper part was stained with amido black. Similar amounts of protein were loaded per lane.