Nucleic Acids Research, 1980, Vol. 8, No. 9 2055-2065
© 1980
Articles |
Synthesis of part of a mouse immunoglobulin light chain in a bacterial clone



*Department of Biochemistry, Weizmann Institute of Science Rehovot, Israel
Department of Chemical Immunology, Weizmann Institute of Science Rehovot, Israel
Received February 25, 1980. We have cloned double stranded cDNA sequences encoding a mouse immunoglobulin light chain (L-321) into the PstI site of the ß-lactamase gene of plasmid pBR322 by the oligo (dG)-oligo (dC) tailing procedure. Escherichia coli XI776 transformed by the recombinant plasmids were screened for the expression of L-321 antigenic determinants by a newly developed in situ radioimmunoassay. One out of seven transformants screened was found to synthesize an L-chain like protein. Each bacterial cell produces about 550 molecules of the L-chain sequence. Preferential segregation of the L-chain sequence into the periplasmic space suggests covalent attachment of the L-chain sequence to the N-terminal portion of ß-lactamase. Restriction mapping of the plasmid DNA Isolated from the positive clone indicated the presence of a DNA sequence coding for the entire constant region and extending into the variable region for a length corresponding to about 40 amino acid residues. The orientation of the cloned cDNA with respect to the plasmid DNA is compatible with the formation of a fused ß-lactamase-L-321 peptide.