title: Association of yeast SIN1 with the tetratrico peptide repeats of CDC23.
abstract: The yeast SIN1 protein is a nuclear protein that together with other proteins behaves as a transcriptional repressor of a family of genes. In addition, sin1 mutants are defective in proper mitotic chromosome segregation. In an effort to understand the basis for these phenotypes, we employed the yeast two-hybrid system to identify proteins that interact with SIN1 in vivo. Here we demonstrate that CDC23, a protein known to be involved in sister chromatid separation during mitosis, is able to directly interact with SIN1. Furthermore, using recombinant molecules in vitro, we show that the N terminal of SIN1 is sufficient to bind a portion of CDC23 consisting solely of tetratrico peptide repeats. Earlier experiments identified the C-terminal domain of SIN1 to be responsible for interaction with a protein that binds the regulatory region of HO, a gene whose transcription is repressed by SIN1. Taken together with the results presented here, we suggest that SIN1 is a chromatin protein having at least a dual function: The N terminal of SIN1 interacts with the tetratrico peptide repeat domains of CDC23, a protein involved in chromosome segregation, whereas the C terminal of SIN1 binds proteins involved in transcriptional regulation.
authors.affiliation: Department of Life Sciences, Bar Ilan University, Ramat Gan, Israel.
authors.forename: S
authors.initials: S
authors.lastname: Shpungin
authors.forename: A
authors.initials: A
authors.lastname: Liberzon
authors.forename: H
authors.initials: H
authors.lastname: Bangio
authors.forename: E
authors.initials: E
authors.lastname: Yona
authors.forename: D J
authors.initials: DJ
authors.lastname: Katcoff
mesh_terms: D000705:Anaphase; D064173:Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000737:chemistry; D011485:Protein Binding; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D043743:Ubiquitin-Protein Ligase Complexes
chemical_list: D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577441:CDC23 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D015345:Oligonucleotide Probes; D029701:Saccharomyces cerevisiae Proteins; C069938:SPT2 protein, S cerevisiae; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome