Post-Transcriptional Regulation of the Sef1 Transcription Factor Controls the Virulence of Candida albicans in Its Mammalian Host
Figure 3
Sfu1 and Ssn3 each physically interact with Sef1 but play opposing roles in Sef1 localization.
a) Overexpression of SSN3 restores nuclear localization of Sef1 to a strain that also overexpresses SFU1. Indirect immunofluorescence of Sef1-Myc in a strain that constitutively overexpresses both SFU1 and SSN3, shown for cells cultured in iron-replete (H) and iron-depleted (L) conditions. Scale bar, 5 µm; all images obtained at the same magnification. b) Sfu1-Myc is co-immunoprecipitated with Sef1-TAP. Wild-type strains containing only Sef1-TAP or both Sef1-TAP and Sfu1-Myc were grown under iron-replete or iron-depleted conditions. Whole cell extracts were prepared under nondenaturing conditions, and IgG-sepharose was used to immunoprecipitate Sef1-TAP and associated proteins. Pellets were subjected to immunoblot analysis, using anti-Myc monoclonal antibodies to identify Sfu1-Myc. c) Sef1-Myc is co-immunoprecipitated with Sfu1-TAP. * indicates a presumed Sef1-Myc C-terminal proteolysis product that is observed only when Sef1 is recovered from nondenaturing extracts, such as those used for TAP purification. d) Sef1-Myc but not Sfu1-Myc is co-immunoprecipitated with Ssn3-TAP. e) Ssn3-Myc is co-immunoprecipitated with Sef1-TAP. * Presumed Sef1-Myc C-terminal proteolysis product, see above.