Dynamics of mRNA Elongation Regulatory Complexes

蛋白质表达水平的改变是由多种机制介导的，包括基因转录的上调和下调，以响应不同的外部刺激，如营养条件。此外，这些细胞还可以通过调节转录后过程（如翻译）来刺激蛋白质水平的产生或抑制。因此，对mRNA表达水平的单一分析并不能充分代表细胞中蛋白质水平上发生的变化。先前的数据表明，在酿酒酵母中，一些转录调节蛋白的水平，包括mRNA延伸复合物的一些成员，在最小培养基中生长时受到转录后机制的调节。我们假设，这些蛋白质含量的变化导致了蛋白质复合物的组成或化学计量学的改变

Alterations in protein expression levels are mediated by a number of mechanisms including the up- and down- regulation of the transcription of genes in response to different external stimuli such as nutrient conditions. In addition, these cells can also stimulate the production or repression of protein levels by modulating post-transcriptional processes such as translation. For this reason, the sole analysis of the levels of mRNA expression does not sufficiently represent the changes that occur at the protein level in the cell. Previous data has indicated that in S. cerevisiae, the levels of a number of transcriptional regulatory proteins including some members of mRNA elongation complexes are regulated by post-transcriptional mechanisms in response to growth in minimal media. We hypothesize that these changes in protein content lead to alterations in either the composition or stoichiometry of the protein complexes involved in the regulation of transcriptional elongation as well as the regulation of other nuclear processes. Using a quantitative proteomics approach, we will determine how changes in the level of protein expression alter the makeup of protein complexes and analyze how these changes alter the gene expression profile of the cell.