Low complexity regions in Biological Matter: Sequences, higher-order assembly, and evolution.

Abstract

From the fibrous silk of a spider to liquid-like nucleoli, biological matter plays important roles in organisms. How does biological matter assemble from component parts, carry out important organismal functions, and evolve in the tree of life? Low complexity regions (LCRs) of proteins are simple protein sequences which have been appreciated to play outsized roles in defining the structures underlying biological matter. However, most LCR sequences do not have known functions. Here I will present my work trying to answer the questions above through developing a unified understanding of LCRs across species. I will present a framework for understanding how LCR copy numbers, sequence relationships, and composition give rise to biological structures. In this thesis I will present work that uses this framework for the identification of novel putative biological assemblies, previously unknown scaffolds underlying biological structures, and shed light on the evolution of biological matter. Together, this work demonstrates that a unified understanding of LCRs can provide novel insight into the structures underlying biological matter.