Our work provides new mechanistic insight into how Notch receptor diversity contributes to epithelial patterning, cell-type specialization, and proliferation control in the vertebrate intestine.

➡️ Notch2 and Notch1b receptors are required for BEST4⁺ cell development
➡️ We demonstrate that BEST4⁺ cells arise from the secretory lineage, resolving a long-standing question about their origin.
➡️ Notch2 mutants lack BEST4⁺ cells and show increased epithelial proliferation

➡️ Following fate specification, a subsequent Notch signaling event (74-76 hpf) drives the differentiation of NRSCs, which we identify here as Bestrophin 4 positive (BEST4⁺) cells.

📌 Key findings:
➡️ Notch2/Notch3 and Notch2/Notch1b receptor combinations are required for the choice between secretory and enterocyte fate in the intestinal epithelium

To address this gap, here we analyzed loss-of-function mutants for all four zebrafish Notch receptors: Notch1a, Notch1b, Notch2, and Notch3

While we have identified the times when Notch signaling is active, the individual Notch receptors involved in each signaling event have not been previously identified.

➡️ 74–76 hpf: a third event involves the differentiation of a unique cell type that we previously called Notch Receiving Secretory Cells (NRSCs)

Notch signaling is utilized at least three times during the development of the intestinal epithelium.
➡️ 30–34 hpf: an early Notch signaling event
➡️ 64–74 hpf: a second event governing the choice between enterocyte and secretory cells' fate

During zebrafish intestinal development, we dissect how individual Notch receptors function at distinct developmental windows to regulate:
➡️ Intestinal secretory vs. enterocyte cell fate choice
➡️ differentiation of BEST4⁺ intestinal cells