At the beginning of May we had the pleasure of welcoming Amy Dowdle from the lab of Julia Horsfield, University of Otago, New Zealand. It was an exciting one week visit as part of a working collaboration between our two labs. The week involved developmentally staging zebrafish embryos to testing morpholinos on the timing of genome activation. We look forward to many more exchanges of knowledge and skills in the future!
From 23rd to 26th April, the MPI-CBG hosted the first international meeting exclusively dedicated to the Maternal-Zygotic Transition (MZT). Under the title "Awakening of the genome: The maternal-to-zygotic transition", a jam-packed meeting program was presented under the umbrella of the EMBO event series.
Focusing on genome activation allowed a first-ever platform for the MZT community. Participants from all over the world gathered to showcase an extensive range of techniques, approaches, and biological questions. Plenty of new and unpublished data made it exciting, a meeting size of ~150 participants meant that everyone could be easily approached, and the wish for a repeat meeting was voiced several times.
Our study demonstrating how repressors (histones) and activators (transcription factors) jointly control transcription in the zebrafish embryo is now available online: Competition between histone and transcription factor binding regulates the onset of transcription in zebrafish embryos. Joseph et al. eLife (2016)
In this study, lead by Shai Joseph (Vastenhouw Lab) and carried out collaboratively with the Shevchenko and Zaburdaev lab, we could quantitatively address a long-standing question: how is the timing at which transcription starts in embryos controlled?
By a combination of quantitative, molecular, and functional techniques, we found that the two most prominent hypotheses, the "depleted repressor" and the "increasing activator" models, can be unified in a competition model. Here, repressing histones and activating transcription factors go head-to-head competing for access to DNA target sites.
Additionally, the nuclear-to-cytoplasmic ratio - often defined in the number of genomes in an embryo - resurfaced as a key concept, though in the form of a volume ratio between cell nuclei and overall cytoplasm. While the global concentration of not DNA-bound histones did not change at the time of transcription onset, we detected a marked decrease in the concentration of not DNA-bound histones specifically within cell nuclei.
A preprint for our latest work is now on BioRxiv: “Competition between histone and transcription factor binding regulates the onset of transcription in zebrafish embryos”. The lead author of this study is Shai, with lots of support from within the Vastenhouw lab as well as the
You can go and read the preprint here: http://biorxiv.org/content/early/2017/04/13/125716
A “Spätzle” night out with Edlyn, as we celebrated our newest addition.
Edlyn also received a book on “How to be German” written in both German & English – a welcome gift as she settles into her new home.
Edlyn was born in Montréal, Canada. She grew up enjoying the Montréal winter and cheering on her favourite hockey team: the Montreal Canadiens. Edlyn majored in Biochemistry at McGill University. She was among the first students to join Dr. Thomas Duchaine’s lab, where she completed her MSc and PhD. Her focus was understanding the mechanism of microRNA-mediated gene silencing, using C. elegans as a model organism. With a passion for traveling, and a long standing interest in zebrafish and early developmental biology, she moved to Europe and joined the Vastenhouw group in January 2017. Edlyn is investigating the molecular events that regulate the timing of zygotic genome activation.
Today, our review on the temporal regulation of zygotic genome activation was published in Current Opinion in Genetics and Development. The review is part of a themed issue of genome architecture and expression, edited by Bart Deplancke and Charles Sagerstrom and contains many more interesting reviews. For the first 50 days, you can download our review for free.
And of course, a little celebration.