CC-1590 act2 mt-
$30.00
Chlamydomonas Genetics Center, Duke University, 1982
Phenotype: antibiotic resistant (cycloheximide)
From a cross of gln1 mt+ x CC-1144 msr1 pyr1 sr1 nr1 act2 pf2 mt-. This strain has the wild type alleles at the GLN1, MSR1, PYR1, NR1, and SR1 loci. The pf2 mutation doesn’t seem to have been scored.
The act2 mutation confers resistance to 5-20 micrograms/ml cycloheximide. 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 for the distal right arm of linkage group VI. The ACT2 locus is very far from the centromere on the right arm of linkage group VI and often does not show linkage to markers on the left arm.
Sager mapped an act mutant isolated in her laboratory 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 designated ACT1 (see CC-1589) and ACT2 respectively. The act2 allele in CC-1590 traces back to Smyth’s multiply marked strain CC-28.
Fleming et al. showed that the original act2 mutation is semi-dominant to its wild type allele in diploids, and that cytoplasmic ribosomes isolated from act2 strains are resistant to cycloheximide in vitro. Resistance was localized to the large subunit of the cytoplasmic ribosome.
Stevens et al. showed that the original act2 is a mutation in the gene encoding protein L41 (yeast nomenclature, = human L44) of the cytoplasmic ribosome. This protein has been annotated as RPL36a in the Chlamydomonas genome sequence.
The mutant cyr1 isolated by J. Goodenough et al. is probably an allele at the ACT2 locus (see CC-1124), as are additional mutants independently isolated by Fleming. Stevens et al. showed that the latter mutations all affect the Pro 54 residue which is changed to Ser in act2c and act2d, and to Leu in act2, act2a, and act2b.
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
Goodenough JE, Bruce VG, Carter A (1981) The effects of inhibitors affecting protein synthesis and membrane activity on the Chlamydomonas reinhardii phototactic rhythm. Biol Bull 161:371-381
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
Stevens DR, Atteia A, Franzén LG, Purton S (2001) Cycloheximide resistance conferred by novel mutations in ribosomal protein L41 of Chlamydomonas reinhardtii. Mol Gen Genet 264:790-795