Browsing by Subject "Tissue adhesion"

Basement membranes (BMs) are thin, dense sheets of extracellular matrix that surround most animal tissues and provide structural support. While the role of BMs in the structural support of tissues is well established, how these matrices can structurally support tissues while accommodating dynamic tissue function is not well understood. Using C. elegans, a powerful model organism that allows for live imaging, genetic analysis, and rapid screening, I was able to utilize endogenous knock-in fluorescent proteins, conditional RNAi, optogenetics, and quantitative live imaging to investigate how BM components contribute to the BM’s ability to withstand mechanical load in various circumstances. In Chapter 1, I discuss the known roles of BM, introduce BM proteins of interest, explore gaps in our understanding of BM’s function in withstanding mechanical force, and expand upon the utility of C. elegans as a model system to investigate these questions. In Chapter 2, I show that BM-to-BM linkages can function to resist the mechanical forces involved in egg-laying. In Chapter 3, I explore how BM stretches to accommodate dynamic tissue movement. In Chapter 4, I discuss future directions and the implications of these findings and in Chapter 5 I summarize my conclusions.

Basement membranes are a specialized type of extracellular matrix found covering most tissues in animals. These structures are made up of many proteins, most notably laminin and type IV collagen, which form separate polymeric networks that are the core of the BM. BMs are involved in many cell and tissue scale processes during development and homeostasis, and misregulation of BM components lies at the heart of many pathologies. Despite their importance, many of the fundamental aspects of BM biology are not well understood. For example, the mechanisms that regulate differences in BM composition, dynamics, and ultrastructure remain largely unknown. One reason for this is the lack of a model to study these processes in vivo. This has also led to BM dependent processes, such as tissue adhesion through BMs, to be largely overlooked. In Chapter 1, I summarize some of my basic knowledge of BMs, highlight important areas that require further study, and review the process of tissue adhesion through BMs. In Chapter 2, I discuss the creation of an in vivo toolkit of endogenously fluorescently labeled BM components, show how these tools can be used to address questions surrounding BM composition and dynamics, and use these tools to identify papilin as a regulator of type IV collagen network architecture in growing tissues. In Chapter three, I explore the process of tissue adhesion through BMs in greater detail, and identify an enrichment of type IV collagen mediated by tissue specific modifications of the BM that is required to maintain stable BM adhesions between tissues. In Chapter 4, I discuss these findings in more detail, their implications, and future directions based off of this work.