A new preprint from the Fukaya Lab has been posted on bioRxiv!

The Drosophila ZAD zinc finger protein Mulberry shapes the organization of the regulatory genome in the early embryo

Yusuke Umemura, Takashi Fukaya

Abstract
Long-range regulatory interactions play a fundamentally important role in the control of gene activity during animal development, yet the underlying mechanisms remain largely unclear. Here, we identified a zinc finger-associated domain (ZAD)-C2H2 zinc finger protein, CG31365/Mulberry, as a looping factor that mediates long-range tethering activity in the early Drosophila embryo. Evidence is provided that Mulberry is specifically recruited to a subset of loop anchors and topological boundaries at key developmental loci to shape genome organization and gene activity. Super-resolution imaging analysis revealed that Mulberry forms nuclear condensates that associate with its target loci through the structured N-terminal ZAD domain. Micro-C analysis further demonstrated that the formation of loops and boundaries is lost in the condensation-deficient Mulberry mutant in a locus-specific manner. We propose that Mulberry acts as a condensation-dependent structural regulator of genome topology, organizing “multi-way regulatory hubs” that mediate long-range gene activation during early embryogenesis.

bioRxiv, doi: 10.64898/2026.02.03.703437. (2026)
https://www.biorxiv.org/content/10.64898/2026.02.03.703437v1