Regulation of tubulin levels and microtubule assembly in Saccharomyces cerevisiae: consequences of altered tubulin gene copy number.

摘要: Microtubule organization in the cytoplasm is part a function of number and length assembled polymers. The intracellular concentration tubulin could specify those parameters. Saccharomyces cerevisiae strains constructed with moderately decreased or increased copy numbers genes provide an opportunity to study cellular response steady-state change concentration. We found no evidence mechanism for adjusting concentrations upward from deficit, nor did we find need such mechanism: cells more than 50% wild-type level were normal respect series microtubule-dependent properties. Strains copies both alpha- beta-tubulin genes, alpha-tubulin alone, apparently down regulate their levels. As result, they contained greater but much less predicted increase gene number. Some this regulation occurred at protein. These also phenotypically normal. Cells contain excess protein without detectable consequences, perturbations resulting may have affected functions. All observed levels can be explained as toxicity associated proteins, especially if toxic alpha-tubulin.