title: PBX1 as Pioneer Factor: A Case Still Open.
abstract: Pioneer factors are proteins that can recognize their target sites in barely accessible chromatin and initiate a cascade of events that allows for later transcriptional activation of the respective genes. Pioneer factors are therefore particularly well-suited to initiate cell fate changes. To date, only a small number of pioneer factors have been identified and studied in depth, such as FOXD3/FOXA1, OCT4, or SOX2. Interestingly, several recent studies reported that the PBC transcription factor PBX1 can access transcriptionally inactive genomic loci. Here, we summarize the evidence linking PBX1 with transcriptional pioneer functions, suggest potential mechanisms involved and discuss open questions to be resolved.
authors.affiliation: Institute of Neurology (Edinger Institute), University Hospital Frankfurt, J. W. Goethe University Frankfurt, Germany.
authors.forename: Britta M
authors.initials: BM
authors.lastname: Grebbin
authors.affiliation: Institute of Neurology (Edinger Institute), University Hospital Frankfurt, J. W. Goethe University Frankfurt, Germany.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Schulte
keywords: PBX; TALE homeodomain protein; adult stem cell; cell fate specification; chromatin remodeling; pioneer factor