A plasmid vector that serves as a dominant marker for isolating transformed animals in Caenorhabditis elegans has been constructed as a translational fusion of the C. elegans act-4 gene (encoding actin) and the Escherichia coli lacZ gene. This gene fusion can be used as a marker in transformation rescue experiments in any fertile strain of C. elegans. Progeny of animals injected with the act-4::lacZ fusion vector are stained histochemically with XGal, and transformants turn blue. The internal eggs of stained animals remain viable, allowing recovery of the transformed strain. When the act-4::lacZ vector is co-injected with an unselected plasmid with which it shares some sequence homology, most transformants that are recovered by screening for expression of the act-4::lacZ fusion contain both plasmids. Production of active ßGal in animals transformed with the act-4::itlacZ gene fusions appears to be limited to certain tissues. A chimeric gene that contains the 5' and 3' regions of act-4 is expressed strongly in the body-wall muscles, vulval muscles, and spermathecae. Addition of the internal portion of act-4, including the protein-coding region and introns, to this chimeric gene leads to additional lacZ expression in the pharynx.
Bibliographical noteFunding Information:
We thank M. Krause for the gift of hact-16, C. Mello for pRF4, M. Nguyen for help in constructing pSS22, S. Xirasagar for help in constructing hact-16-lacZ, and J.S. Gantt for help with the manuscript. Some nematode strains used in this work were provided by the Caenorhabditis Genetics Center, which is funded by the NIH National Center for Research Resources. This research was supported by NSF grant DCB-87113 to J.E.S.
- muscle expression
- pharyngeal expression