Department Chair

I. Martha Skerrett, Chair and Associate Professor of Biology

Date of Award


Access Control

Open Access

Degree Name

Biology, M.A.


Biology Department


Gregory J. Wadsworth, Ph.D., Associate Professor of Biology

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First Reader

Gregory J. Wadsworth, Ph.D., Associate Professor of Biology

Second Reader

Douglas P. Easton, Ph.D., Research Professor of Biology

Third Reader

Derek L. Beahm, Ph.D., Research Assistant Professor of Biology


Abstract of a Thesis

Differential Regulation of the Two grp170 Paralogues of Caenorhabditis elegans

Caenorhabditis elegans has two loci encoding the large eukaryotic molecular chaperone Grp170, grp170a (T24H7.2) and grp170b (T14G8.3). To investigate expression of the two C. elegans grp170 loci during ER stress, the Unfolded Protein Response (UPR) was induced with the glycosylation inhibitor tunicamycin. Levels of grp170a mRNA did not significantly change in response to tunicamycin treatment while the levels of grp170b mRNA increased 6-fold. ER stress induction of grp170b was unaffected in worms defective for the ATF6 and PERK-1 UPR signal transduction pathways. However, worms defective for the IRE-1 dependent UPR pathway failed to induce grp170b. The expression of grp170 mRNA was analyzed in nematodes homozygous for the grp170a deletion allele tm3109 or for the grp170b deletion allele ok502. Expression of grp170a mRNA was unaffected by the loss of grp170b. In contrast, grp170b was induced 83 fold in nematodes deficient for grp170a. To further investigate whether loss of either grp170 loci induces UPR, the expression of another UPR responsive gene, hsp-4, was analyzed. In nematodes lacking grp170b, expression of hsp-4 mRNA was not affected. However, in nematodes lacking grp170a, the UPR responsive hsp-4 mRNA was up-regulated 38 fold. These data suggest that while grp170a plays a critical role in ER protein folding, it is not itself inducible by the UPR. On the other hand grp170b seems to play a less critical role in protein folding under non-stress conditions, it is the grp170 locus that is induced by the UPR.

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