Studies on the basis of ethionine-resistance in neurospora

• Published in: Biochimica et biophysica acta Vol. 107; no. 3; pp. 425 - 433
• Main Authors: Kappy, Michael S., Metzenberg, Robert L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 18.10.1965
• Subjects: Drug Resistance, Microbial; Ethionine - metabolism; In Vitro Techniques; Methionine - biosynthesis; Mutation; Neurospora - metabolism; Protein Biosynthesis
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/0304-4165(65)90186-8

1. 1. The basis of ethionine resistance in two temperature-sensitive irreparable mutants of Neurospora crassa (55701 and r-eth-1) has been examined. 2. 2. One of these mutants (55701) appears to be resistant due to an impaired ability to concentrate ethionine from the medium. 3. 3. The strain r-eth-1 has a normal uptake system for ethionine, but fails to incorporate this analog into protein. Evidence is offered that although r-eth-1 overproduces methionine, this fact accounts for only part of the resistance to ethionine, and that this strain has an ability to discriminate against this analog that is not a trivial consequence of methionine overproduction. 4. 4. It is proposed that a single gene alteration in r-eth-1 genes rise to three pleiotropic effects: (a) a component of the protein-synthesizing machinery is able to discriminate between methionine and ethionine, (b) this component is involved in the regulation of methionine synthesis, (c) the change in this component renders it abnormally temperature-labile.