Defects in protein trafficking affect expression of GPCRs in C. elegans

In the nematode C. elegans, the bilaterally symmetric PVQ neurons are located in the tail and each extends an axon along the ventral nerve cord to the head. Several G protein coupled receptors (EGL-47, SRA-6) are terminally expressed in PVQ as well as a limited number of other neurons. Mutations in six genes (tba-1, unc-14, unc-33, unc-44, unc-51, unc-119) known to disrupt axon outgrowth were found to eliminate expression of sra-6::gfp and egl-47::gfp in PVQ soon after hatching. Expression of sra-6::gfp was high in embryos and newly hatched L1 larvae, yet the GFP signal was greatly reduced within 2-3 hours and was typically not detectable after 10 hours. Expression of sra-6::gfp in the chemosensory neurons, ASH and ASI, was not affected. Previous studies reported that UNC-119 is an acylated protein transporter, and is required for transporting G protein α-subunits and other acylated proteins. However, loss of function of unc-119 does not affect the expression of G protein. Together, these results suggest that protein trafficking defects resulting from the loss of UNC-119 in turn lead to a reduction in gene transcription of sra-6 and egl-47. To understand further how these six genes affect transcription, we undertook a genetic screen to isolate mutations that restore expression of sra-6::gfp in PVQ in unc-119 mutants. Eight suppressors that define two genes were isolated. Unc-119 animals harboring a suppresser mutation still exhibit a strong Dpy and Unc unc-119 phenotype and PVQ still has axon outgrowth defects. As such, these suppressors are specific to the restoration of sra-6::gfp expression in PVQ and do not appear to rescue other unc-119 functions. The suppressors are also specific to unc-119 and do not restore expression of sra-6 in the other mutants.

Level thesis:degree_level

Doctorate Degree

Year dc:date.issued

2015

Author dc:creator

• Gorzalski, Andrew J.

Advisor dc:contributor.advisor

• Clark, Scott G.

Committee members dc:contributor.committeemember

• Kidd, Thomas
• Berninsone, Patricia
• Keene, Alex
• Miller, Glenn

• C. elegans
• gene expression
• GPCR
• Trafficking

Statement dc:rights

• In Copyright(All Rights Reserved)

Handle dc:identifier.uri

http://hdl.handle.net/11714/2500

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/2500