title: TFIIIC localizes budding yeast ETC sites to the nuclear periphery.
abstract: Chromatin function requires specific three-dimensional architectures of chromosomes. We investigated whether Saccharomyces cerevisiae extra TFIIIC (ETC) sites, which bind the TFIIIC transcription factor but do not recruit RNA polymerase III, show specific intranuclear positioning. We show that six of the eight known S. cerevisiae ETC sites localize predominantly at the nuclear periphery, and that ETC sites retain their tethering function when moved to a new chromosomal location. Several lines of evidence indicate that TFIIIC is central to the ETC peripheral localization mechanism. Mutating or deleting the TFIIIC-binding consensus ablated ETC -site peripheral positioning, and inducing degradation of the TFIIIC subunit Tfc3 led to rapid release of an ETC site from the nuclear periphery. We find, moreover, that anchoring one TFIIIC subunit at an ectopic chromosomal site causes recruitment of others and drives peripheral tethering. Localization of ETC sites at the nuclear periphery also requires Mps3, a Sad1-UNC-84-domain protein that spans the inner nuclear membrane. Surprisingly, we find that the chromatin barrier and insulator functions of an ETC site do not depend on correct peripheral localization. In summary, TFIIIC and Mps3 together direct the intranuclear positioning of a new class of S. cerevisiae genomic loci positioned at the nuclear periphery.
authors.affiliation: Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom.
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Hiraga
authors.forename: Sotirios
authors.initials: S
authors.lastname: Botsios
authors.forename: David
authors.initials: D
authors.lastname: Donze
authors.forename: Anne D
authors.initials: AD
authors.lastname: Donaldson
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D064447:Checkpoint Kinase 2; D002843:Chromatin / Q000502:physiology; D004258:DNA Polymerase III; D015966:Gene Expression Regulation, Fungal; D008565:Membrane Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012320:RNA Polymerase III / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D019474:Transcription Factors, TFIII / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000098832:Transcription Factor TFIIIC
chemical_list: D018797:Cell Cycle Proteins; D002843:Chromatin; D008565:Membrane Proteins; C471174:Mps3 protein, S cerevisiae; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D019474:Transcription Factors, TFIII; D000098832:Transcription Factor TFIIIC; D064447:Checkpoint Kinase 2; D017346:Protein Serine-Threonine Kinases; C067022:RAD53 protein, S cerevisiae; C041273:transcription factor tau; D012320:RNA Polymerase III; D004258:DNA Polymerase III