title: SAF-A has a role in transcriptional regulation of Oct4 in ES cells through promoter binding.
abstract: Methodologies to reprogram somatic cells into patient-specific pluripotent cells, which could potentially be used in personalized drug discovery and cell replacement therapies, are currently under development. Oct4 activation is essential for successful reprogramming and pluripotency of embryonic stem (ES) cells, albeit molecular details of Oct4 activation are not completely understood. Here we report that endogenous SAF-A is involved in regulation of Oct4 expression, binds the Oct4 proximal promoter in ES cells, and dissociates from the promoter upon early differentiation induced by LIF withdrawal. Depletion of SAF-A decreases Oct4 expression even in the presence of LIF, and results in an increase of the mesodermal marker Brachyury. The overexpression of wild-type human SAF-A rescues the mouse knock-down phenotype and results in increased Oct4 level. We also demonstrate that endogenous SAF-A interacts with the C-terminal domain (CTD) of endogenous RNA polymerase II and that the interaction is independent of CTD phosphorylation and mRNA. Moreover, we show that SAF-A exist in complexes with transcription factors Sox2 and Oct4 as well as STAT3 in ES cells. The number of endogenous SAF-A:Oct4 and SAF-A:Sox2 complexes decreases upon LIF depletion. These discoveries allow us to propose a model for activation of Oct4 transcription.
authors.affiliation: Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, University of Gothenburg , Gothenburg, Sweden.
authors.forename: Dzeneta
authors.initials: D
authors.lastname: Vizlin-Hodzic
authors.forename: Helena
authors.initials: H
authors.lastname: Johansson
authors.forename: Jessica
authors.initials: J
authors.lastname: Ryme
authors.forename: Tomas
authors.initials: T
authors.lastname: Simonsson
authors.forename: Stina
authors.initials: S
authors.lastname: Simonsson
mesh_terms: D000818:Animals; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000166:cytology / Q000502:physiology*; D005786:Gene Expression Regulation; D034722:Heterogeneous-Nuclear Ribonucleoprotein U / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D050814:Octamer Transcription Factor-3; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C558468:SAF-A protein, mouse; D055748:SOXB1 Transcription Factors; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; D012319:RNA Polymerase II