PAR-3 is Sufficient to Remodel Cystic Intestines in C. elegans
Faculty Mentor Information
Dr. Melissa Pickett, College of Idaho
Presentation Date
7-16-2026
Abstract
All metazoans use specialized epithelial cells to build selectively permeable barriers between body systems. The establishment and maintenance of apico-basolateral polarity, with certain conserved proteins targeted to the apical (outside facing) epithelial cell surface and others targeted to the basolateral cell surfaces is necessary for barrier and organ function. Loss of polarity contributes to several known diseases, including polycystic kidney disease, microvillus inclusion disease, and cancer. In the model roundworm, C. elegans, intestine specific degradation of the conserved scaffolding protein, PAR-3, disrupts polarity establishment and causes worms to hatch with discontinuous, cystic intestines instead of continuous hollow intestines. Surprisingly, if PAR-3 is expressed in these cystic intestines after PAR-3 is normally required, the cystic intestines can remodel, forming continuous hollow tubes. We want to understand how effective this remodeling process is for generating functional intestines. We hypothesized that the remodeled intestines would be less functional when compared with control worms that established intestinal polarity normally during embryogenesis. We tested barrier function by feeding control worms and worms with remodeled intestines blue dyed bacteria and examine leakage of the dye out of the intestine. We also examined lifespan as worms with disrupted barrier function have shorter lifespans and worms that have decreased nutrient uptake have increased lifespans. In contrast to our predictions, our results suggest that the remodeled intestines act effectively as barriers and are efficient in the transport of nutrients as we have found no differences in either barrier leakage or in lifespan.
PAR-3 is Sufficient to Remodel Cystic Intestines in C. elegans
All metazoans use specialized epithelial cells to build selectively permeable barriers between body systems. The establishment and maintenance of apico-basolateral polarity, with certain conserved proteins targeted to the apical (outside facing) epithelial cell surface and others targeted to the basolateral cell surfaces is necessary for barrier and organ function. Loss of polarity contributes to several known diseases, including polycystic kidney disease, microvillus inclusion disease, and cancer. In the model roundworm, C. elegans, intestine specific degradation of the conserved scaffolding protein, PAR-3, disrupts polarity establishment and causes worms to hatch with discontinuous, cystic intestines instead of continuous hollow intestines. Surprisingly, if PAR-3 is expressed in these cystic intestines after PAR-3 is normally required, the cystic intestines can remodel, forming continuous hollow tubes. We want to understand how effective this remodeling process is for generating functional intestines. We hypothesized that the remodeled intestines would be less functional when compared with control worms that established intestinal polarity normally during embryogenesis. We tested barrier function by feeding control worms and worms with remodeled intestines blue dyed bacteria and examine leakage of the dye out of the intestine. We also examined lifespan as worms with disrupted barrier function have shorter lifespans and worms that have decreased nutrient uptake have increased lifespans. In contrast to our predictions, our results suggest that the remodeled intestines act effectively as barriers and are efficient in the transport of nutrients as we have found no differences in either barrier leakage or in lifespan.