Gene Composer software, Vector construct assembly viewer. Virtual construction of expression vectors with designed gene inserts is accomplished through the Vector Construct Assembly Viewer shown here. All vectors, adaptor assemblies, and engineered gene constructs are stored in the Gene Composer database. Virtual cloning starts with the selection of all gene constructs that are to be cloned (upper left, Construct window). The user then selects a desired plasmid expression vector (pBACgus displayed as black circular arrow). Based on data associated with the expression vector, the Gene Composer software is cognizant of the intended point of insertion for the protein open reading frame (green arc). The sequence details are shown with a radial sequence viewer (blue wedge), which displays the nucleic acid sequence in that region (window with blue arrows). User defined adaptor assemblies (Adaptor Assembly window, lower left) are used to combine the selected expression vector with desired gene construct inserts (orange line). The user arranges the adapters in the order desired, selects a vector from the pull-down menu and the software assembles the elements into a final construct. In the example shown, there is a BamHI restriction site (blue square) at the 5' end of the insert, while the 3' end contains an in frame hexa-histidine (His6) amino acid affinity tag sequence (orange square), a double translation terminator (black square), and a HindIII restriction site (green square). The amino acid sequence of the construct plus added tags is also displayed.