Structure and Function of the Ankyrin Repeats in the SW14/SW16 Transcription Complex of Budding Yeast.
Annual rept. 8 Jul 95-7 Jul 96,
FRED HUTCHINSON CANCER RESEARCH CENTER SEATTLE WA
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Ankyrin repeats are motifs of thirty three amino acid residues, which are found in over 100 proteins. Several of these are of particular interest because they suggest roles for the ankyrin repeat in tumor development. ANK repeats were first identified in a pair of yeast transcription factors Sw14 and Sw16, and this research is focused upon understanding the role of the ANK repeats within these proteins. We have generated libraries of PCR-generated mutants of the Sw16 ANK domain and analyzed them with respect their transcriptional activity and sequence changes. We also used site-directed mutagenesis to systematically remove the core residues from each of the 4 ANK repeats, and found that the ANK core mutants as well as many of the random mutants are temperature sensitive for activity. This suggests that this region of the Swi6 protein is critical for the stability of the protein. We then isolated high copy suppressors of these mutants. Two gene products known to be involved in transcription and DNA interaction were identified NHP6A and MSNl as well as a novel protein PIBi. The significance of these interactions is under investigation