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Title: Studies on the regulation and function of the itr-1 gene in Caenorhabditis elegans
Author: Gower, N. J. D.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2003
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Conservation in genomic structure of itr-1 and the Caenorhabditis briggsae orthologue of itr-1, Chitr-1, was used to confirm that itr-1 has three promoters, termed pA, pB and pC. Promoter fusions to GFP were used to demonstrate that each promoter drives tissue-specific expression of ITR-1. Synteny between itr-1 and Chitr-1 sequences identified conserved boxes within each promoter and those in promoter pA were assayed for their role as regulatory factor binding sites. The results showed that certain boxes contained the information for cell-specific expression of itr-1. One such box termed C1-C2, which is responsible for itr-1 expression in the pharyngeal terminal bulb and rectal epithelial cells, was used to identify PHA-4 a member of the forkhead/HNF-3 family of transcription factors as a key regulator of itr-1 expression. PHA-4 binds to a site within C1-C2 with high affinity and removal of this site from the promoter pA reporter construct removes expression in the pharyngeal terminal bulb. Knockdown of itr-1 by RNA-mediated interference (RNAi) identified a role for ITR-1 in the up-regulation of pharyngeal pumping in response to food. It was also used to confirm the role of ITR-1 in defecation, ovulation and ventral enclosure. Cell specific expression of a dominant-negative IP3 'sponge' directed by the three itr-1 promoters was used to further dissect these functions. RNAi or itr-1 in males identified a significant role for ITR-1 in male fertility. Defects were identified in male turning ability and rate of spicule insertion however the most striking defect was their inability to transfer sperm into the hermaphrodite. The expression patterns in males directed by the three itr-1 promoters were characterised and based on these and the RNAi results predictions were made regarding potential roles of ITR-1 in male specific structures.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available