Expression of tagged mutant versions of LC1. (a) Map of the ∼6.2-kb LC1 genomic region, indicating the location of the five exons and the sites of myc tag insertion and mutagenesis. The genomic fragment also includes the gene for GMP synthase. (b) Southern blot analysis of SmaI-digested genomic DNA from strains transformed with various mutant forms of LC1. The endogenous LC1 gene yields a SmaI fragment of ∼4.5 kb (Benashski et al., 1999). The additional bands represent ≥1 integrated copies of the tagged LC1 gene. (c) Immunoblot analysis of flagellar samples from 11 strains transformed with the R189A mutant LC1 gene. The myc-tagged LC1 protein is detectable in five strains. (d) Immunoblot analysis of selected M182G- and M182P-transformed strains. These strains were chosen for analysis, as they stably express approximately similar amounts of wild-type and mutant LC1 proteins.