A NOVEL STRATEGY FOR THE IMMUNOLOGICAL TAGGING OF CDNA CONSTRUCTS

We describe the construction of pBact-myc, an expression vector that i ncorporates an immunological 'tag' into the produced polypeptide. When transfected into recipient cell lines, tagged protein fragments deriv ed from any source can be visualised using a single monoclonal antibod y (mAb). The neuronal microtubule-associated protein 2c (MAP2c) was ta gged with a sequence encoding a peptide from the human c-myc gene. The preservation of normal function of the tagged protein was shown by tr ansfecting it into cultured cell lines. No difference in binding abili ty to cellular microtubules could be observed between the myc-tagged M AP2c and the wild-type forms, and both produced the same characteristi c changes in microtubule organisation. This approach is being used to study the biological function of selected fragments of MAP2c and other MAP-encoding genes. The pBact-myc expression vector represents a fast and convenient way to produce tagged polypeptides of selected sequenc es encoding whole proteins or fragments, for the analysis of their fun ction in living cells.