Ribosomal Biogenesis and Endomembrane Expansion Precede Cell Invasion

Cell invasion through basement membrane (BM) barriers is necessary for development and homeostasis, and is misappropriated in diseases like cancer. Many regulators of this complex biological process have been identified by relying on studies completed in vitro and through the analysis of genetic mutants in vivo, however, these methods are unable to identify redundant and subtle regulators of invasion. Capturing the gene expression profile of a cell actively transmigrating BM in vivo remains elusive as invasion through BM is often random. However, a gene expression profile would shed light on genes and pathways that have previously gone unnoticed using traditional screening methods. Here, I use the C. elegans model of anchor cell (AC) invasion through BM as a visually and genetically tractable in vivo model utilizing forward and reverse genetic screening, transcriptome profiling, split-GFP protein tagging strategies, and live cell imaging to investigate and identify new regulators and cellular processes controlling cell invasion through BM. In Chapter 1, I review strategies and mechanisms that invasive cells employ to breach and travel through BM and present AC invasion in C. elegans as an in vivo model of cell invasion. In Chapter 2, I attempt to identify two new regulators of AC invasion identified through a large-scale forward genetic screen. In Chapter 3, by developing methods to isolate individual AC’s, I identify the AC transcriptional profile during invasion, I reveal key roles for ribosome biogenesis and endomembrane expansion in cell invasion through BM and establish the AC transcriptome as a resource to identify mechanisms underlying BM transmigration. Chapter 4 discusses the implications of these findings and future directions.