Interactions between Saccharomyces cerevisiae YEATS Domain-Containing Yaf9 and Swc4 Proteins

Abstract

The YEATS domain is a conserved histone mark reader implicated in the regulation of chromatin structure and transcription. In Saccharomyces cerevisiae, the YEATS domain-containing protein Yaf9 is a subunit of SWR1 and NuA4 chromatin remodelling complexes. In both, it directly interacts with a shared subunit Swc4. This study investigated the Yaf9-Swc4 interaction and possible Yaf9 role outside of its complex-associated functions. A series of Yaf9 deletion mutants truncated at different regions of the protein were constructed using overlap extension PCR and were introduced into yeast. Protein interactions were examined using co-immunoprecipitation, and mutant strains were phenotyped via stress assays involving formamide exposure. The results revealed that deletions in the C-terminal region of Yaf9, as well as within the 160-168 amino acid region – located in the YEATS domain, but outside of the domain’s primary reader region – disrupted interaction with Swc4 and phenocopied a full YAF9 deletion under stress. Additionally, results of this work show that Yaf9 likely does not act independently of both complexes. These findings highlight regions of Yaf9 required for Swc4 association and enhance understanding about the protein’s function. Moreover, these data provide a basis for protein studies in higher eukaryotes.