| Yeast Tral protein is the only subunit that is common in both chromatin remodeling complexes SAGA and NuA4 and is also a direct target of many transcriptional activators involved in a large number of cellular processes. Tral protein can affect transcription via three possible ways, by affecting direct recruitment of Tral-containing complexes to its target promoters, by altering the integrity and stability of the Tral-containing chromatin remodeling complexes SAGA and NuA4, and by disturbing the patterns of histone modification. This thesis is aimed to explore the mechanism how Tral mutation affects the pattern of gene expression in yeast using two different technical approaches, i.e. co-immunoprecipitation and microarray analysis. Tral mutant strains, Tral-1 and Tral-2, have been prepared previously in our laboratory. The first objective is to examine the integrity and stability of the chromatin remodeling complexes SAGA and NuA4 in Tral mutant strains using co-immunoprecipitation. The second objective is to find out the immediate target genes affected by Tral mutation through microassay analysis. By comparing the microarray results obtained with various Tral mutant strains under steady-state condition at sub-lethal temperature with the results obtained 30 min. after shifting the cultures from permissive temperature to restricted temperature, we might be able to deduce the major target genes and the pathways involved regulated by Tral-containing complexes and the affected cascades leading to the manifestation of the mutant phenotypes. Co-immunoprecipitation results show that the two Tral mutants, Tral-1 and Tral-2, influence the stability of the chromatin remodeling complexes SAGA and NuA4. The effect is more serious for Tral-2 than for Tral-1. The microassay results show that the Tral mutations mainly influence genes involved in ribosome biogenesis and energy metabolism. This information is valuable to a detailed understanding of the mechanism how Tral functions in the cells. |
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