RT Journal Article SR Electronic T1 Competition between histone and transcription factor binding regulates the onset of transcription in zebrafish embryos JF bioRxiv FD Cold Spring Harbor Laboratory SP 125716 DO 10.1101/125716 A1 Joseph, Shai R. A1 Pálfy, Máté A1 Hilbert, Lennart A1 Kumar, Mukesh A1 Karschau, Jens A1 Zaburdaev, Vasily A1 Shevchenko, Andrej A1 Vastenhouw, Nadine L. YR 2017 UL http://biorxiv.org/content/early/2017/04/13/125716.abstract AB SUMMARY Upon fertilization, the genome of animal embryos remains transcriptionally inactive until the maternal-to-zygotic transition. At this time, the embryo takes control of its development and transcription begins. How the onset of zygotic transcription is regulated remains unclear. Here, we show that a dynamic competition for DNA binding between nucleosome-forming histones and transcription factors regulates zebrafish genome activation. Taking a quantitative approach, we found that the concentration of non-DNA bound core histones sets the time for the onset of transcription. The reduction in nuclear histone concentration that coincides with genome activation does not affect nucleosome density on DNA, but allows transcription factors to compete successfully for DNA binding. In agreement with this, transcription factor binding is sensitive to histone levels and the concentration of transcription factors also affects the time of transcription. Our results demonstrate that the relative levels of histones and transcription factors regulate the onset of transcription in the embryo.