Biology subjects

Tan, S. Z.

Publications and source records attributed to Tan, S. Z..

4 recordsLinked to original sources

bioRxiv2026

A Cre-responsive reporter quail for flexible genetic lineage tracing

Genetic lineage tracing is a powerful approach for investigating cell fate and tissue development, but versatile Cre/loxP-based tools remain limited in avian models. Here, we generated and characterised a Cre-responsive transgenic quail line that enables permanent genetic labelling of embryonic cell populations. The reporter line ubiquitously expresses nuclear-localised mCherry, which is excised following Cre-mediated recombination, enabling expression of nuclear-localised EGFP. We demonstrate that this reporter can be coupled to multiple Cre delivery strategies, providing flexible spatial and temporal control of lineage labelling. Ubiquitous or cell-type-specific Cre expression induces recombination and stable EGFP labelling that is maintained during clonal expansion. Optogenetic activation of a split Cre system enables highly spatially and temporally restricted recombination. Furthermore, lipid nanoparticle-mediated delivery of Cre mRNA enables efficient recombination in distinct embryonic cell populations, including mesodermal, neuroepithelial, neural crest, endothelial and circulating cells. This transgenic reporter quail provides a flexible platform for permanent lineage labelling without the need to generate tissue-specific Cre transgenic lines and can be readily combined with diverse Cre delivery strategies to investigate cell fate, lineage and morphogenesis in vivo.

developmental biology↗

bioRxiv2025

Quantitative live imaging reveals PRICKLE1 controls junctional neural tube morphogenesis independent of Planar Cell Polarity

Neurulation, the process that forms the neural tube--the precursor to the brain and spinal cord--is frequently disrupted in congenital malformations. Primary and secondary neurulation are integrated at a junctional zone, yet the cellular dynamics linking these programs remain unknown. Using high-resolution quantitative live imaging in transgenic quail embryos, we show that the junctional neural tube forms through two coordinated processes: mediolateral convergence and EMT-driven ingression of medial neuroepithelial cells. We demonstrate that PRICKLE1, a core PCP protein, orchestrates these behaviors independently of planar polarity cues. PK1 is enriched at the apical cortex of medial cells, where it drives actomyosin accumulation and apical constriction. This function is essential for both convergence and cell ingression but is uncoupled from classical PCP axis establishment. Our findings redefine the molecular basis of junctional neurulation and implicate impaired EMT as a central cause of localized neural tube defects.

developmental biology↗

bioRxiv2023

The Lifeact-EGFP Quail: A New Avian Model for Studying Actin Dynamics In Vivo

Here we report the generation of a transgenic Lifeact-EGFP quail line for the investigation of actin organization and dynamics during morphogenesis in vivo. This transgenic avian line allows for the high-resolution visualization of actin structures within the living embryo, from the subcellular filaments that guide cell shape to the supracellular assemblies that coordinate movements across tissues. The unique suitability of avian embryos to live imaging facilitates the investigation of previously intractable processes during embryogenesis. Using high-resolution live imaging approaches, we present the dynamic behaviours and morphologies of cellular protrusions in different tissue contexts. Furthermore, through the integration of live imaging with computational segmentation, we reveal the dynamics of cells undergoing apical constriction and the emergence of large-scale actin structures such as supracellular cables and rosettes within the neuroepithelium. These findings not only enhance our understanding of tissue morphogenesis but also demonstrate the utility of the Lifeact-EGFP transgenic quail as a new model system for live in vivo investigations of the actin cytoskeleton.

developmental biology↗

bioRxiv2019

Early origin and deep conservation of enhancers in animals

Transcription factors (TFs) bind DNA enhancer sequences to regulate gene transcription in animals. Unlike TFs, the evolution of enhancers has been difficult to trace because of their rapid evolution. Here, we show enhancers from the sponge Amphimedon queenslandica can drive cell type-specific reporter gene expression in zebrafish and mouse, despite sponge and vertebrate lineages diverging over 700 million years ago. Although sponge enhancers, which are present in both highly conserved syntenic gene regions (Islet-Scaper, Ccne1-Uri and Tdrd3-Diaph3) and sponge-specific intergenic regions, have no significant sequence identity with vertebrate genomic sequences, the type and frequency of TF binding motifs in the sponge enhancer allow for the identification of homologous enhancers in bilaterians. Islet enhancers identified in human and mouse Scaper genes drive zebrafish reporter expression patterns that are almost identical to the sponge Islet enhancer. The existence of homologous enhancers in these disparate metazoans suggests animal development is controlled by TF-enhancer DNA interactions that were present in the first multicellular animals.\n\nOne-sentence summaryEnhancer activity is conserved across 700 million years of trans-phyletic divergence.

evolutionary biology↗