CIS REGULATORY REQUIREMENTS FOR HYPODERMAL CELL-SPECIFIC EXPRESSION OF THE CAENORHABDITIS-ELEGANS CUTICLE COLLAGEN GENE DPY-7

The Caenorhabditis elegans cuticle collagens are encoded by a multigen e family of between 50 and 100 members and are the major component of the nematode cuticular exoskeleton, They are synthesized in the hypode rmis prior to secretion and incorporation into the cuticle and exhibit complex patterns of spatial and temporal expression, We have investig ated the cis regulatory requirements for tissue- and stage-specific ex pression of the cuticle collagen gene dpy-7 and have identified a comp act regulatory element which is sufficient to specify hypodermal cell reporter gene expression. This element appears to be a true tissue-spe cific promoter element, since it encompasses the dpy-7 transcription i nitiation sites and functions in an orientation-dependent manner, We h ave also shown, by interspecies transformation experiments, that the d py-7 cis regulatory elements are functionally conserved between C, ele gans and C, briggsae, and comparative sequence analysis supports the i mportance of the regulatory sequence that we have identified by report er gene analysis. All of our data suggest that the spatial expression of the dpy-7 cuticle collagen gene is established essentially by a sma ll tissue-specific promoter element and does not require upstream acti vator or repressor elements. In addition, we have found the DPY-7 poly peptide is very highly conserved between the two species and that the C, briggsae polypeptide can function appropriately within the C, elega ns cuticle, This finding suggests a remarkably high level of conservat ion of individual cuticle components, and their interactions, between these two nematode species.