The single transmembrane segment of gp210 is sufficient for sorting to the pore membrane domain of the nuclear envelope

Chimeric cDNAs encoding the fusion proteins CD8/gp(TM + CT), CDS/gp(TM + CT)-20, and CDS/gp(TM + CT)-54 (see Fig. 1 ) were constructed as follows, pSP65FI was digested with XbaI and EcoRV to produce a DNA fragment containing nucleotides 1-611 of the CD8 eDNA (18) . The 3' blunt-end site created by EcoRV follows the codon for amino acid residue 161 (18) . This fragment was combined separately with each of three PCR products that encode amino acid residues 1,806-1,886 ( Fig. 1 ). In each PCR product the gp210 coding region is followed by a 3' termination codon and a BamHI linker. The CD8 eDNA fragment was blunt-end ligated to each of the PCR products to produce the appropriate chimeric eDNA and subeloned into a Xbal and BamHI cut pSVL plasmid.