Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Biology and Microbiology

First Advisor

Natalie Thiex


CRISPR/Cas9, Macrophage, Macropinocytosis, Mannose Receptor, whole genome screen


Macrophages maintain tissue homeostasis by identifying and eliminating threats within their tissue microenvironment. Pattern recognition receptors allow macrophages to recognize and internalize specific ligands while macropinocytosis allows the internalization of all extracellular solutes from their environment. Without pattern recognition receptors, pathogens may grow unchecked if they cannot be detected, and without macropinocytosis, macrophages struggle to detect and move around their environment. This thesis presents the results of CRISPR/Cas9 whole-genome screens used to identify the regulators of both endocytosis (Chapter 2) and macropinocytosis (Chapter 3). In Chapter 2, we report genes regulating dextran uptake in primary murine macrophages and reveal Mrc1-mediated endocytosis, instead of macropinocytosis, as the primary internalization mechanism mediating dextran uptake. In Chapter 3, to specifically target macropinocytosis, we present the results of CRISPR/Cas9 whole genome screens to identify genes regulating lucifer yellow uptake in primary macrophages. We observed that regulation of both the endo-lysosomal system and mTor signaling complex as essential for regulating macropinocytosis. This thesis establishes a framework for understanding how primary macrophages regulate both endocytic and macropinocytic processes. We can use this information to identify therapies and treatments to stimulate or inhibit Mrc1-medaited endocytic processes or macropinocytosis. Macrophages may be selectively targeted with therapeutics dependent on either Mrc1 or macropinocytosis for delivery. Our research may provide new insights for how we can improve therapies delivered to cells using Mrc1 or macropinocytosis.



Number of Pages



South Dakota State University


In Copyright - Non-Commercial Use Permitted (2944 kB)
Supplementary Data Files (Zip file)

Available for download on Tuesday, December 20, 2022