P-ELEMENT MEDIATED GERM-LINE TRANSFORMATION OF DROSOPHILA-MELANOGASTER WITH THE TCL TRANSPOSABLE DNA ELEMENT FROM CAENORHABDITIS-ELEGANS

Questions relating to the origin and regulation of mobile genetic elem ents are currently of considerable interest. Since it is now possible to address more precisely issues concerning the entry, dispersion, and regulation of elements within a virgin genome, one approach that may afford a better understanding of transposable elements in general coul d be provided by interspecific DNA transformation. Therefore, the Tcl transposable DNA element from Caenorhabditis elegans was chosen as a p roposed invading element of the Drosophila melanogaster genome. The ba sis for this selection resided in the inherent structural and function al similarities, as well as sequence identities, between the Caenorhab ditis element and elements innate to Drosophila (e.g., P, HBl, and Uhu ). Initial investigations were carried out to define a clone carrying an intact Tcl element. This Tcl element was inserted into a P transpos on vector and two P-Tcl-ry(+) constructs, differing only in insert ori entation, were identified. P element mediated germ line transfer was t hen used to generate a transformant that was genetically and molecular ly identified as containing a single, structurally intact Tcl element at cytological location 64C4-5 on the third chromosome. The single P[( Tcl,ry(+))]SAS-B insertion was thereafter mobilized by using a P[ry(+) Delta 2-3] element as a transposase source, and the genetic and molecu lar data suggested that the insertion had been successfully reintegrat ed to a variety of genomic locations. On the basis of genetic and mole cular analyses, the Tcl element in the P[(Tcl,ry(+))] transformed stoc k is not highly unstable in germ line and somatic tissues.