Meeting Abstract
LEA proteins are highly hydrophilic, intrinsically disordered proteins that are critically important for the survival of a variety of small anhydrobiotic invertebrates during desiccation. LEA proteins found in Artemia francicana are comprised of groups 1, 3 and 6. The precise physiological function of LEA proteins during osmotic stress and desiccation is poorly understood. The aim of this study was to assess how the expression of one or more LEA proteins impacted the viability of Kc167 (D. melanogaster) cells during prolonged osmotic stress or desiccation. Relative drying times were determined by desiccating Kc167 cells at three different relative humidities (RH) (0%, 32.5%, and 75.5%). Times to reach similar residual moisture contents in cell samples increased with increasing relative humidity. Cell viabilities after desiccation were found to depend on both residual moisture content and drying time. Kc167 cells were stably transfected to express AfrLEA3m-mCherry (group 3) and AfrSMP-GFP (group 6) concurrently. In addition, expression of AfrLEA2 (group 3) or AfrLEA3m without fluorescence tags was also achieved. After prolonged desiccation at 75.5% RH, Kc167 cells expressing both AfrLEA3m-mCherry and AfrSMP-GFP outperformed cells expressing AfrLEA3m alone. However, both transformed cell lines showed significantly higher viabilities than control cells. In addition, cells expressing AfrLEA2 showed higher viability than control cells after both 24h and 48h of prolonged osmotic stress. Surprisingly, AfrLEA3m demonstrated no such protection. These data suggest expressing multiple LEA proteins simultaneously can further enhance desiccation tolerance and that LEA proteins from the same classification group may serve different protective roles (NSF IOS-1456809/1457061).
