Subategory:

Mutants

Description:

The 28-7J chloroplast mutant was recovered by screening a collection of acetate-requiring mutants for lack of complementation with a known Rubisco rbcL mutant. The mutant was crossed with pf2 mt- to confirm uniparental inheritance, and this mt+ progeny clone was analyzed. Mutant 28-7J results from an R217S substitution (CGT-AGT) in the chloroplast-encoded large subunit of Rubisco, which blocks Rubisco holoenzyme assembly. Selection for photosynthesis-competent revertants yielded true revertants, intragenic suppressors (see R14-A), and heteroplasmic suppressors that likely arise from heteroplasmic informational (tRNA) suppression. This strain has been maintained with acetate medium in darkness since its isolation.

Species:

Chlamydomonas

Locus:

rbcL

Chromosome:

Chloroplast

Phenotype:

Requires acetate; sensitive to light