FIGURE 2.

Three RDRC subunits are not essential for vegetative growth. Gene disruption for RDN1, RDN2, RDF1, and RDF2 was performed by integration of a selectable marker cassette in two independent strains, CU522 and SB210. Southern blot analysis of genomic DNA was performed separately for each locus, using the restriction enzymes and probes shown in the schematics. Neo-S and Neo-R indicate relative phenotypic sensitivity and resistance to the selective drug. The appropriate wild-type (WT) and disrupted locus fragment sizes are indicated to the right of each blot. Incomplete loss of the endogenous RDN1 locus indicates that the strains are gene knockdown (KD) in the polyploid macronucleus; complete loss of RDN2, RDF1, or RDF2 indicates that these strains are gene knockouts (KO).