Open Access Te Herenga Waka-Victoria University of Wellington
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A Novel System for Monitoring in vivo Cell Signaling Pathways Involved in Early Embryonic Patterning

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posted on 2021-11-22, 10:50 authored by Rooney, Louise

Early developmental events, such as the arrangement of the head-tail axis, are fundamentally driven by cell signalling cascades. Such incidents are regulated in a highly complex manner by promoters and inhibitors at many levels of the cascade. This complexity makes it difficult to understand where and when certain signalling occurs, and what effects additional factors have on the signalling system. Nodal signalling, executed by intracellular Smad2/3 signal propagation, is thought to induce the anterior-posterior and head-tail patterning of the early mouse embryo. Target gene outputs of this signalling are fine-tuned by a vast array of modulators; TGBβ co-receptors, extracellular ligand and receptor inhibitors, DNA binding cofactors, and intracellular enhancers and inhibitors. The endogenous target genes of this system cannot be used as a measure of signalling as they themselves feedback on the original system and others, creating diverse signals. In this body of work, we have distilled the Nodal signalling cascade to a single variable by creating a fluorescent genetic reporter to semi-quantitatively measure Smad signalling during early embryonic development. Reporter constructs contain Smad binding elements, a minimal promoter and fluorescent protein elements. Various sensitivity Smad binding elements were created to respond to different thresholds of signalling. Fluorescent microscopy and flow cytometry were used to verify responsiveness of reporter constructs, tested first in a mouse embryonic fibroblast line and subsequently in transgenic embryos. This study will provide an understanding of how extracellular cues dictate gene expression during early embryonic formation. The knowledge acquired from this work may have implications in dairy cattle and human fertility.


Copyright Date


Date of Award



Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Biomedical Science

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level


Degree Name

Master of Biomedical Science

ANZSRC Type Of Activity code

970106 Expanding Knowledge in the Biological Sciences

Victoria University of Wellington Item Type

Awarded Research Masters Thesis



Victoria University of Wellington School

School of Biological Sciences


Pfeffer, Peter