Fig. 2.

Sterility phenotype of Chlamydomonas vsr1 mutants. (A) Diagram of RWP11 (VSR1) locus and location of CIB1 cassette in exon 2 (E2) of mutant strain LMJ.RY0402.189640 whose mutant allele is designated as vsr1-1. Locations and names of PCR primers used for genotyping are shown above. Exons are indicated by thick black boxes and labeled E1 to E9. 5′ and 3′ untranslated regions (UTRs) are indicated by thinner dark gray lines. (B) PCR genotyping of VSR1 and vsr1-1 alleles. PCR products were run on agarose gels and imaged after staining with RedSafe dye. Strain CC-5325 MT^– is the parent strain of vsr1-1 and serves as a wild-type control. A no-template control for each primer pair is designated as –. (C) Mating reactions between pairs of indicated strains (or CC-5325 as a negative control). Top row of tubes shows gamete suspensions just after mixing. Bottom row shows tubes after an overnight incubation. Successful mating results in buoyant mats of zygote pellicle on the surface and sides of the tube and a clear appearance. (D) Matings from panel (C) were spread in sectors on an agar plate prior to pellicle formation, allowed to mature, and chloroform treated to kill unmated gametes prior to germination. Colonies are formed by germinated zygospores.