LEA motifs promote desiccation tolerancein vivo

Abstract

Cells and organisms typically cannot survive in the absence of water. However, there are some notable exceptions, including animals such as nematodes, tardigrades, rotifers, and some arthropods. One class of proteins known to play a role in desiccation resistance is the late embryogenesis abundant (LEA) proteins. These largely disordered proteins protect plants and animals alike from desiccation. A multitude of studies have characterized stress-protective functions of LEA proteins in vitro and in heterologous systems. However, the extent to which LEA proteins exhibit the same functions in their native contexts in animals is unclear. Furthermore, nothing is known about the distribution of LEA proteins in multicellular organisms or tissue-specific requirements in conferring stress protection. To study the endogenous function of LEA proteins in an animal, we created a true null mutant of C. elegans LEA-1, as well as endogenous fluorescent reporters of the protein. We confirmed that C. elegans lacking LEA-1 are sensitive to desiccation. LEA-1 mutant animals were also sensitive to heat and osmotic stress and were prone to protein aggregation. During desiccation, LEA-1 expression increased and became more widespread throughout the body. LEA-1 was required at high levels in body wall muscle for animals to survive desiccation and osmotic stress. We identified minimal motifs within LEA-1 that are sufficient to increase desiccation survival of E. coli. Our results provide insights into the endogenous functions and expression dynamics of an LEA protein in a multicellular animal. We show that LEA-1 buffers animals from a broad range of stresses. Our identification of functional motifs within the protein suggests the possibility of engineering LEA-1-derived peptides for desiccation protection.