Worm Breeder's Gazette 11(4): 57
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
To identify the control regions of the C. elegans gut-specific esterase gene (ges-1), we are using a variety of approaches including a comparison of the upstream control regions of ges-1 and the homologous esterase gene from C. briggsae (cloned and sequenced from the Baillie library by Brian Kennedy and Fran Allen). For this approach to be valid, we needed to show that the esterase gene from one species is properly expressed in the other species. It was easy to show that the C. briggsae esterase is expressed in the gut of C. elegans by transforming the C. briggsae gene into a ges-1(0) strain of C. elegans and then staining the transformants for esterase. We did this experiment using both transient transformation and extrachromosomal heritable transformation. To show that the C. elegans properly expressed in C. briggsae, we needed to make a strain of C. briggsae that was transformed with the C. elegans tried the rol-6 dominant mutant gene and followed the transformation procedure of Mello et al. (WBG 11-1:18 and WBG 11-3:12). Roller strains of C. briggsae were easily obtained (the rachis of C. briggsae is even easier to hit than that of C. elegans). When the ges-1 gene was used in a cotransformation with the rol-6 gene all of the esterase expression was confined to the guts of the transformants i.e. the transformants looked exactly like wildtype C. briggsae. We then used isoelectric focusing gels on extracts of the transformed C. briggsae followed by staining of the gel for esterase activity to show that the C. elegans indeed being expressed. Thus, the C. elegans expressed in C. briggsae and it is expressed only in the gut. A deleted construct of ges-1 that contains only 521 base pairs 5' from the translation initiation codon is expressed in the pharynx muscles of C. elegans (E. Aamodt, M. Chung and J. McGhee, manuscript submitted). When this deleted ges-1 gene was transformed into C. briggsae, the transformants also express the esterase gene in their pharynx. In other words, not only is the intact gene properly expressed but the ectopic expression of the deleted ges-1 is identical between the two species. Thus, both ges-1 and the mutant rol-6 genes are properly expressed in C. briggsae. Cotransformation of C. briggsae using the rol-6 marker gene should be useful to others who wish to see if their favorite C. elegans gene works in C. briggsae.