[Subcellular fluorescence localization analysis of all SAGA subunits in fission yeast (Schizosaccharomyces pombe)].

SAGA(Spt-Ada-Gcn5 Acetyltransferase complex) is a multi-subunit and conservative transcription complex, which is composed of 19 subunits in fission yeast and regulates the transcription of 10% genes in vivo. Through constructing in situ integrated fluorescence strains, we analyzed subcellular fluorescence localization of all SAGA subunits. Microscopic data showed localization manners could be sorted by 4 types, suggesting that these SAGA subunits may have additional functions besides transcriptional regulation. Subunit Sgf73 is the bridge that connects deubiquitination module and other SAGA modules, lacking of sgf73+ not only significantly reduced nuclear fluorescence localization (NFL) of deubiq-uitination subunits Ubp8, Sgf11, Sus1, but also affected NFL of acetylation subunits Gcn5, Sgf29, Ngg1, and the core structure subunit Spt7.The impact indicates that Sgf73 is important to maintain enzymatic function and stabilization of SAGA. Moreover, deletion of sgf73+ also caused a cytokinesis defect, which is characterized by a multi-nucleus and multi-septum phenotype. Overexpressing ace2+ and mid2+ in Dsgf73, which are key genes involved in septum degradation, showed that ace2+ could not rescue the defect, and mid2+ could only partially compensate for the deficiency, suggesting that Sgf73 may play a role in other pathways that affect cytokinesis.