Worm Breeder's Gazette 8(3): 95
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.
Working in collaboration with Richard Jefferson in David Hirsh's lab at MCDB in Boulder we have been studying the expression of transformed genes in C. elegans. Using an MSP promoter from C. elegans in pUC9 recombinant plasmids have been constructed bearing an MSP promoter fused in-frame to the structural sequence for E. coli -glucuronidase followed by an MSP terminator sequence. This plasmid (pMSP 2.1: UIDA) has been injected into the gonads of adult hermaphrodites. Progency have been found bearing pMSP 2.1:UIDA sequences as extrachromosomal long tandern repeats with a copy number of approximately 200. These extrachromosomal elements are 80% stable ie., 80% of the progeny from a positive adult contain the plasmid. DAPI staining of oocytes during late diplotene reveals small chromosome like fragments in addition to the 6 tetrads. These fragments are approximately 1/10 the intensity and size of a C. elegans chromosome. Some oocytes are observed to contain more than one such element and 3 and 4 elements have been seen in some oocytes. Some oocytes do not contain any elements. Significant levels of -glucuronidase are present in the transformed worms (DH 408-762) in contrast to no activity in the nontransformed ( DH 408) strain. We are currently investigating the regulation of the -glu gene by Northern blot analysis and by the in situ localization of the enzyme. We are also searching among the transformants for stable integrated copies of the plasmid.