The plastocyanin-deficient phenotype of Chlamydomonas reinhardtii Ac-208 results from a frame-shift mutation in the nuclear gene encoding preapoplastocyanin.

Ac-208 is a plastocyanin-deficient mutant of Chlamydomonas reihardtii that contains only 2-3% of the wild-type level of plastocyanin-encoding mRNA and no detectable plastocyanin. Sequence analysis of the ac-208 plastocyanin-encoding gene reveals a single nucleotide insertion in the first exon compared with the wild-type gene; this alters the reading frame and results in a premature nonsense codon. We have introduced the genomic sequence encoding plastocyanin from a wild-type strain into ac-208 by cotransformation with a selectable marker encoding nitrate reductase