PT  - JOURNAL ARTICLE
AU  - Jingyue Ellie Duan
AU  - Leila E. Rieder
AU  - Annie Huang
AU  - William T. Jordan III
AU  - Mary McKenney
AU  - Scott Watters
AU  - Nicolas L. Fawzi
AU  - Erica N. Larschan
TI  - CLAMP and Zelda function together as pioneer transcription factors to promote <em>Drosophila</em> zygotic genome activation
AID  - 10.1101/2020.07.15.205054
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.07.15.205054
4099  - http://biorxiv.org/content/early/2020/07/15/2020.07.15.205054.short
4100  - http://biorxiv.org/content/early/2020/07/15/2020.07.15.205054.full
AB  - Because zygotic genome activation (ZGA) is an essential process across metazoans, it is key to evolve multiple pioneer transcription factors (TFs) to protect organisms from loss of a single factor. Pioneer TF Zelda (ZLD) is the only known factor which increases accessibility of chromatin to promote ZGA in the early Drosophila embryo. However, many genomic loci remain accessible without ZLD and have GA-rich motifs. Therefore, we hypothesized that other pioneer TFs that function with ZLD have not yet been identified in early embryos, especially those that bind to GA-rich motifs, such as CLAMP (Chromatin-linked adaptor for Male-specific lethal MSL proteins). Here, we determine that CLAMP is a novel pioneer TF which interacts directly with nucleosomes, regulates zygotic genome transcription, promotes chromatin accessibility, and facilitates the binding of ZLD to promoters. Thus, the maternal factor CLAMP functions with ZLD as a pioneer TF to open chromatin and drive zygotic genome activation.Competing Interest StatementThe authors have declared no competing interest.