The Bicaudal-C repression domain couples translational silencing to maternal embryonic patterning
Year: 2026
Type: article
Abstract: The maternal period of embryonic development occurs before zygotic transcription is active and therefore relies heavily on post-transcriptional mechanisms such as regulated mRNA translation. Central to this regulation are RNA-binding proteins (RBPs), yet how individual RBPs orchestrate maternal gene regulation remains poorly understood. Bicaudal-C (Bicc1) is a conserved RBP and translational repressor that selects mRNAs through N-terminal KH domains and represses their translation through C-terminal activities whose mechanisms remain unclear. In the maternal Xenopus embryo, Bicc1 represses mRNAs encoding cell-fate regulators to establish the anterior/posterior axis. Here, we define the activities of the Bicc1 repression domain (Bicc1-RD). We show that the RD is sufficient for poly(A)-independent translational repression and mediates interactions with diverse RNA regulatory factors, including Bicc1 itself, the CCR4-NOT complex, and the translational regulators Lsm14, 4E-T, and Ddx6. Functional analyses reveal that RD activities are essential for maternal Bicc1-dependent patterning but dispensable for its zygotic role in left/right patterning, demonstrating mechanistically distinct Bicc1 repression strategies across developmental stages. These findings reveal how a modular RBP can coordinate stage-specific translational control during embryogenesis.
Source: Development
DOI: 10.1242/dev.205916
Language: English
Topic: RNA Research and Splicing
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
OpenAlex ID: W7225402380