Caenorhabditis elegans is a model organism for studying genetics and neuroscience C. elegans is frequently studied to understand how genes and the environment interact to produce new phenotypes. We take advantage of an organism-wide stress response and genetic tools that provide an excellent model for studying how phenotypes are impacted by stress

Androwski, Rebecca

Rose, Becky

Schroeder, Nathan E.

English

Scholarship at Parkland

Becky Rose,1 Rebecca Androwski,2 and Nathan E. Schroeder2,3Lincoln Land Community College, Springfield, Illinois1Neuroscience Program, University of Illinois at Urbana-Champaign2Department of Crop Sciences, University of Illinois at Urbana-Champaign3Stress Induced Remodeling in the Nematode C. elegansAcknowledgmentsFinancial support was provided by the National Science Foundation under grant #NSF REU 1559908/1559929, as part of the Phenotypic Plasticity Research Experience for Community College Students, through the University of Illinois at Urbana-Champaign Institute for Genomic Biology and Parkland College. http://precs.igb.illinois.edu/I want to thank Rebecca Androwski for her patient, supportive and instructive mentoring, the Schroeder lab for their constant support and assistance, PRECS Principal Investigators Dr. Nathan Schroeder and Dr. C. Britt Carlson for their investment in my educational and personal development, the PRECS staff for all the working lunches and behind the scenes support, the technical and support staff at the Institute for Genomic Biology, and the NSF for this incredible opportunity.References1. lenbach, N. & Antebi, A. (2008). C-elegans dauer formation and the molecular basis of 532 plasticity. Genes & Development 22, 2149-2165, doi: 10.1101/gad.170150.2. Cassada R.C., and Russell R.L. (1975). The dauer larva, a post-embryonic developmental variant of the nematode Caenorhabditis elegans. Developmental Biology, 46, 326–342.3. Androwski, R. J., Flatt, K. M., & Schroeder, N. E. (2017). Phenotypic plasticity and remodeling in the stress-induced Caenorhabditis elegans dauer. Wiley interdisciplinary reviews. Developmental biology, 6(5), 10.1002/wdev.278. doi:10.1002/wdev.2784. Hu, P.J. Dauer (August 08, 2007), WormBook, ed. The C. elegans Research Community, WormBook, doi/10.1895/wormbook.1.144.1, http://www.wormbook.org5. Pablo Garcia-Junco-Clemente & Peyman Golshani. (2014). PTEN, Communicative & Integrative Biology, 7:2, doi: 10.4161/cib.28358.6. Image retrieved on July 15, 2019 from https://wormbase.org/species/c_elegans/gene/WBGene00002147#01-9g-37. Wei, X., Howell, A. S., Dong, X., Taylor, C. A., Cooper, R. C., Zhang, J., … Shen, K. (2015). The unfolded protein response is required for dendrite morphogenesis. eLife, 4, e06963. doi:10.7554/eLife.06963.8. Kulalert, W., & Kim, D. H. (2013). The unfolded protein response in a pair of sensory neurons promotes entry of C. elegans into dauer diapause. Current biology : CB, 23(24), 2540–2545. doi:10.1016/j.cub.2013.10.058.Caenorhabditis elegans is a model organism for studying genetics and neuroscienceC. elegans is frequently studied to understand how genes and the environment interact to produce new phenotypes. We take advantage of an organism-wide stress response and genetic tools that provide an excellent model for studying how phenotypes are impacted by stress.  Stress-resistant dauer stageCrowded conditions and lack of food cause C. elegans to enter an alternative stress-resistant stage called dauer. Dauers undergo multiple morphological changes including, thickening of the cuticle, radial shrinkage, and neuroplasticity.1Dauer morphology provides resistance to 1% sodium dodecyl sulfate (SDS).2There is extensive remodeling of the IL2 neurons during dauerOutside of dauer the six IL2 dendrites are unbranched. During dauer they form elaborate branches that cover the head of the animal. Once the animal recovers from dauer, the branches resorb and return to their unbranched morphology.daf-18 is required for IL2 branchingThe candidate gene, daf-18, encodes a PTEN homolog in C. elegans.4 PTEN is a critical component of human neurological health. Mutations in PTEN lead to abnormal neuronal growth and neurological dysfunction and are hypothesized to be a cause of autism spectrum disorder.5  When C. elegans daf-18/PTEN is disrupted, we found IL2 dendrite branching defects. IRE-1 activates a stress response that plays a critical role in regulating dendrite growthConclusions• daf-18/PTEN is required for IL2 branching• ire-1 is a critical component in the IL2 branching pathway• We found allelic differences between ire-1(ok799) and ire-1(v33)• ire-1(ok799) appears to have an intermediate resistance to SDS as compared to non-daueranimals• ire-1(v33) appears to lack resistance to SDS as compared to non-dauer animalsFuture Work• Perform more SDS dose response replicates for ire-1(ok799)• Perform SDS dose response replicate at lower concentration (0.01%) for ire-1(v33)• Look at other highly branched neurons in daf-18 adult mutants to determine effect of mutation outside of IL2s• Look at IL2s in non-dauer daf-18 mutants Figure 2: Neuroplasticity of IL2 neurons during dauer The IL2 dendrites (A) are unbranched  in non-daueranimals. During dauer, the dendrites (B) branch extensively. White arrow indicates primary dendrite. Red arrow indicates body wall branch during dauer. The IL2s are labeled using klp-6p::gfp. Scale bar is 10 µm.3Figure 1:  Environmental stress causes an alternate larval stage called dauer. Upon return to favorable environmental conditions the animal recovers from dauer and resumes normal development.  daf-18; [IL2::gfp] [IL2::gfp]Wild type non-dauer [IL2::gfp]Dauer [IL2::gfp]ire-1 (ok799); [IL2::gfp][IL2::gf]Figure 3 The daf-18 mutant showed a lack of IL2 branching. The IL2s are labeled using klp-6p::gfp. Scale bar is 10 µm.Previously both alleles have been considered to completely disrupt protein function.7,8 ire-1(v33) and ire-1(ok799) have been linked separately to dauer formation and to neuronal defects, respectively.7,8 We found branching defects in both alleles. However, we found these defects at low penetrance where only 20% of the animals had severe defects.ire-1 (v33); [IL2::gfp]ABAre ire-1 mutants true dauers?We did a 1% SDS test to isolate dauers of each allele. Exposure to 1% SDS is a common way to isolate truedauers. None of the (v33) animals survived and only 3 of the (ok799) animals survived.  Interestingly, these results contradicted literature that stated (v33) mutants form 100% dauers.8 This led us to question whether these animals were true dauers. We then performed SDS dose response assay to assess susceptibility. We used the following SDS concentrations: 1%, 0.5%, 0.2%, 0.1%.Figure 6  ANOVA and Tukey’s Multiple Comparison Test were performed.  ire-1(ok799): n=20 for 0.2% and n=60 for 0.5%. Ire-1(v33): n=60 for all treatments. Dauer is negative control; non-dauer is positive control. For (ok799), there was a significance between the non-dauer and 0.5% treatment but no significance between non-dauer and 0.2%. For (v33), there was no significance between non-dauer and any treatment. Different letters indicate statistical significance.Non-dauer Mutant dauerWT dauer20 worms & M9 buffer SDSIncubate with shaking for 30 minutes Count surviving/dead wormsABBCCAB B BBSurvival RateSurvival RateWe looked at two variations of ire-1, (v33) and (ok799).Figure 5 ire-1(ok799) and ire-1(v33) are representative of severe branching defects (A,B). The IL2s are labeled using klp-6p::gfp. Scale bar is 10 µm.ASDS ResultsFigure 4 ire-1(ok799) and ire-1(v33) are both large deletions.6

Stress Induced Remodeling in the Nematode C. elegans

SPARK: Scholarship at Parkland | Parkland College

Becky Rose,1 Rebecca Androwski,2 and Nathan E. Schroeder2,3
Lincoln Land Community College, Springfield, Illinois1
Neuroscience Program, University of Illinois at Urbana-Champaign2
Department of Crop Sciences, University of Illinois at Urbana-Champaign3
Stress Induced Remodeling in the Nematode C. elegans
Acknowledgments
Financial support was provided by the National Science Foundation 
under grant #NSF REU 1559908/1559929, as part of the Phenotypic 
Plasticity Research Experience for Community College Students, 
through the University of Illinois at Urbana-Champaign Institute for 
Genomic Biology and Parkland College. http://precs.igb.illinois.edu/
I want to thank Rebecca Androwski for her patient, supportive and 
instructive mentoring, the Schroeder lab for their constant support and 
assistance, PRECS Principal Investigators Dr. Nathan Schroeder and 
Dr. C. Britt Carlson for their investment in my educational and 
personal development, the PRECS staff for all the working 
lunches and behind the scenes support, the technical and 
support staff at the Institute for Genomic Biology, and the 
NSF for this incredible opportunity.
References
1. lenbach, N. & Antebi, A. (2008). C-elegans dauer formation and the molecular basis of 532 
plasticity. Genes & Development 22, 2149-2165, doi: 10.1101/gad.170150.
2. Cassada R.C., and Russell R.L. (1975). The dauer larva, a post-embryonic developmental variant 
of the nematode Caenorhabditis elegans. Developmental Biology, 46, 326–342.
3. Androwski, R. J., Flatt, K. M., & Schroeder, N. E. (2017). Phenotypic plasticity and remodeling in 
the stress-induced Caenorhabditis elegans dauer. Wiley interdisciplinary reviews. Developmental 
biology, 6(5), 10.1002/wdev.278. doi:10.1002/wdev.278
4. Hu, P.J. Dauer (August 08, 2007), WormBook, ed. The C. elegans Research Community, 
WormBook, doi/10.1895/wormbook.1.144.1, http://www.wormbook.org
5. Pablo Garcia-Junco-Clemente & Peyman Golshani. (2014). PTEN, Communicative & Integrative 
Biology, 7:2, doi: 10.4161/cib.28358.
6. Image retrieved on July 15, 2019 from 
https://wormbase.org/species/c_elegans/gene/WBGene00002147#01-9g-3
7. Wei, X., Howell, A. S., Dong, X., Taylor, C. A., Cooper, R. C., Zhang, J., … Shen, K. (2015). The 
unfolded protein response is required for dendrite morphogenesis. eLife, 4, e06963. 
doi:10.7554/eLife.06963.
8. Kulalert, W., & Kim, D. H. (2013). The unfolded protein response in a pair of sensory neurons 
promotes entry of C. elegans into dauer diapause. Current biology : CB, 23(24), 2540–2545. 
doi:10.1016/j.cub.2013.10.058.
Caenorhabditis elegans is a model organism for 
studying genetics and neuroscience
C. elegans is frequently studied to understand how genes and the environment interact to 
produce new phenotypes. We take advantage of an organism-wide stress response and 
genetic tools that provide an excellent model for studying how phenotypes are impacted by 
stress.  
Stress-resistant dauer stage
Crowded conditions and lack of food cause C. elegans to enter an alternative stress-resistant 
stage called dauer. 
Dauers undergo multiple morphological changes including, thickening of the cuticle, radial 
shrinkage, and neuroplasticity.1
Dauer morphology provides resistance to 1% sodium dodecyl sulfate (SDS).2
There is extensive remodeling of the IL2 neurons during dauer
Outside of dauer the six IL2 dendrites are unbranched. During dauer they form elaborate 
branches that cover the head of the animal. Once the animal recovers from dauer, the branches 
resorb and return to their unbranched morphology.
daf-18 is required for IL2 branching
The candidate gene, daf-18, encodes a PTEN homolog in C. elegans.4 PTEN is a critical component of 
human neurological health. Mutations in PTEN lead to abnormal neuronal growth and neurological 
dysfunction and are hypothesized to be a cause of autism spectrum disorder.5  When C. elegans daf-
18/PTEN is disrupted, we found IL2 dendrite branching defects. 
IRE-1 activates a stress response that plays a critical role in 
regulating dendrite growth
Conclusions
• daf-18/PTEN is required for IL2 branching
• ire-1 is a critical component in the IL2 branching pathway
• We found allelic differences between ire-1(ok799) and ire-1(v33)
• ire-1(ok799) appears to have an intermediate 
resistance to SDS as compared to non-dauer
animals
• ire-1(v33) appears to lack resistance to SDS as 
compared to non-dauer animals
Future Work
• Perform more SDS dose response replicates for ire-1(ok799)
• Perform SDS dose response replicate at lower concentration 
(0.01%) for ire-1(v33)
• Look at other highly branched neurons in daf-18 adult 
mutants to determine effect of mutation outside of IL2s
• Look at IL2s in non-dauer daf-18 mutants 
Figure 2: Neuroplasticity of IL2 neurons during dauer The IL2 dendrites (A) are unbranched  in non-dauer
animals. During dauer, the dendrites (B) branch extensively. White arrow indicates primary dendrite. Red arrow 
indicates body wall branch during dauer. The IL2s are labeled using klp-6p::gfp. Scale bar is 10 µm.3
Figure 1:  Environmental stress causes an alternate larval stage called dauer. Upon return to favorable 
environmental conditions the animal recovers from dauer and resumes normal development.  
daf-18; [IL2::gfp] [IL2::gfp]
Wild type non-dauer [IL2::gfp]
Dauer [IL2::gfp]
ire-1 (ok799); [IL2::gfp]
[IL2::gf]
Figure 3 The daf-18 mutant showed a lack of IL2 branching. The IL2s are labeled using klp-6p::gfp. Scale bar is 10 µm.
Previously both alleles have been considered to completely disrupt protein function.7,8 ire-1(v33) and ire-
1(ok799) have been linked separately to dauer formation and to neuronal defects, respectively.7,8 We 
found branching defects in both alleles. However, we found these defects at low penetrance where 
only 20% of the animals had severe defects.
ire-1 (v33); [IL2::gfp]
A
B
Are ire-1 mutants true dauers?
We did a 1% SDS test to isolate dauers of each allele. Exposure to 1% SDS is a common way to isolate true
dauers. None of the (v33) animals survived and only 3 of the (ok799) animals survived.  Interestingly, these 
results contradicted literature that stated (v33) mutants form 100% dauers.8 This led us to question whether 
these animals were true dauers. We then performed SDS dose response assay to assess susceptibility. We 
used the following SDS concentrations: 1%, 0.5%, 0.2%, 0.1%.
Figure 6  ANOVA and Tukey’s Multiple 
Comparison Test were performed.  ire-
1(ok799): n=20 for 0.2% and n=60 for 
0.5%. Ire-1(v33): n=60 for all treatments. 
Dauer is negative control; non-dauer is 
positive control. For (ok799), there was a 
significance between the non-dauer and 
0.5% treatment but no significance 
between non-dauer and 0.2%. For (v33), 
there was no significance between non-
dauer and any treatment. Different letters 
indicate statistical significance.
Non-dauer Mutant dauerWT dauer
20 worms & M9 buffer SDS
Incubate with shaking for 30 minutes Count surviving/dead worms
A
B
BC
C
A
B B B
B
S
u
rv
iv
a
l 
R
a
te
S
u
rv
iv
a
l 
R
a
te
We looked at two variations of ire-1, (v33) and (ok799).
Figure 5 ire-1(ok799) and ire-1(v33) are representative of severe branching defects (A,B). The IL2s are labeled using klp-
6p::gfp. Scale bar is 10 µm.
A
SDS Results
Figure 4 ire-1(ok799) and ire-1(v33) are both large deletions.6


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Stress Induced Remodeling in the Nematode C. elegans

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