CC-1589 act1 mt+
$30.00
Chlamydomonas Genetics Center, Duke University, 1982
Phenotype: antibiotic resistant (cycloheximide)
From a cross of CC-1036 pf18 mt+ to a strain that eventually became CC-1712 act1 ac12 mt-. This strain has the wild type alleles at the PF18 and AC12 loci.
The act1 mutation was isolated by Sager and Tsubo, and confers resistance to 5-20 micrograms/ml cycloheximide (trade name Actidione). Some preliminary testing may be required to establish a concentration of the antibiotic that kills wild type cells but permits growth of the mutant. At the correct concentration, however, this mutant is easy to score and makes a good genetic marker.
Sager mapped this locus to linkage group II, near AC12. Smyth et al. (1975) thought that the act mutant under investigation by their group was identical with Sager’s mutant, but found that theirs mapped to linkage group VI. Assignment of these two mutations to II and VI respectively was confirmed by crosses at the Chlamydomonas Genetics Center, and the loci were therefore designated ACT1 and ACT2.
Fleming et al. showed that the act1 allele is dominant in diploids, and that cytoplasmic ribosomes isolated from act1 strains are resistant to cycloheximide in vitro. Resistance was localized to the large subunit of the cytoplasmic ribosome, but no protein alteration could be detected on two-dimensional gel electrophoresis. The mutant gene has not been cloned and sequenced yet. However, a candidate gene is RPL27a, which maps to approximately the same location as ACT1 on chromosome 2. (Note that the primary gene encoding actin has also been called ACT1. This mutation has nothing to do with that gene.)
Smyth RD, Martinek GW, Ebersold WT (1975) Linkage of six genes in Chlamydomonas reinhardtii and the construction of linkage test strains. J Bacteriol 124:1615-1617
Fleming GH, Boynton JE, Gillham NW (1987) The cytoplasmic ribosomes of Chlamydomonas reinhardtii: characterization of antibiotic sensitivity and cycloheximide-resistant mutants. Mol Gen Genet 210:419-428