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A constitutive mutation in a posttranscriptional regulator gene for a phenoloxidase and proteases in Podospora
Abstract:
A recessive mutation in the gene mod-2 results in the synthesis at low temperatures of a phenoloxidase and an arrest of growth, reversible by beta-phenyl-pyruvic acid, a protease inhibitor. Phenoloxidase synthesis is 5-fluorouracil resistant and cycloheximade sensitive. Suppression of both cold sensitivity and phenoloxidase synthesis by common factors (higher NH4+ concentrations or mutations) suggests that the protease, suspected to be responsible for cold sensitivity, also arises from preexisting mRNA molecules. Instead of being recessive and constitutive, the mod-2 mutations is suppressive and dominant when cold sensitivity and phenoloxidases synthesis are induced as the consequence of the nonallelic gene interactions C/D, C/E, or R/V responsible for protoplasmic incompatibility. Combinations of nonallelic incompatibility systems and several mod-2 mutations lead us to hypothesize that the translational control of the above proteins depends on conformational relationships between incompatibility gene products and mod-2.
Insights
A mutation in the mod-2 gene causes cold-sensitive growth arrest and phenoloxidase synthesis, regulated by translational control. This process is influenced by gene interactions and protein conformational relationships.
Area of Science:
- Molecular biology
- Genetics
- Biochemistry
Background:
- The gene mod-2 is implicated in cellular processes.
- Phenoloxidase synthesis and growth arrest are observed under specific conditions.
Purpose of the Study:
- To investigate the role of the mod-2 gene in regulating phenoloxidase synthesis and cold sensitivity.
- To explore the translational control mechanisms involving mod-2 and gene interactions.
Main Methods:
- Analysis of a recessive mutation in the mod-2 gene.
- Investigating the effects of temperature, beta-phenyl-pyruvic acid, 5-fluorouracil, and cycloheximide on phenoloxidase synthesis.
- Examining the impact of ammonium ion concentration and nonallelic gene interactions on cold sensitivity and phenoloxidase production.
Main Results:
- The mod-2 mutation leads to low-temperature synthesis of phenoloxidase and reversible growth arrest.
- Phenoloxidase synthesis is resistant to 5-fluorouracil but sensitive to cycloheximide.
- Common factors suppress both cold sensitivity and phenoloxidase synthesis, suggesting a protease derived from pre-existing mRNA.
- mod-2 mutations exhibit suppressive and dominant behavior under conditions of protoplasmic incompatibility due to nonallelic gene interactions.
Conclusions:
- The protease responsible for cold sensitivity appears to be synthesized from existing mRNA molecules.
- Translational control of proteins, including phenoloxidase, is dependent on conformational relationships between incompatibility gene products and mod-2.