897-901Saccharomyces cerevisiae
cells
when grown on synthetic medium plates containing 10 mM of
4-aminopyridine (4-AP) undergo cell lysis. Using an ethylmethane sulfonate
mutagenesis (EMS) screen, 4-AP resistant
mutants (apr) were isolated which could grow on inhibitory
concentration of 4-AP. Eighty mutants were obtained that were recessive,
monogenic and
formed two complementation groups. To
identify genes, whose products might be interacting with the apr loci, extragenic
suppressors were isolated, which reverted 4-AP resistance phenotype of apr mutants.
The suppressors, when genetically characterized, were found to be recessive and
represented two loci with overlapping functions. Representative alleles from
apr <span style="font-size:12.0pt;
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were analyzed for cell wall composition. They were found to have a higher
amount of alkali-insoluble glucan signifying the role of alkali-insoluble glucan
in cell wall maintenance.</span