Patent ID: 7794971
Filing Date: 2010-09-14
Classification: C12N

Abstract:
1. A method for cloning and stably maintaining a DNA sequence encoding a foreign product in a host cell, said method comprising: A. providing: B. ligating said DNA sequence encoding the foreign product into a plasmid, which DNA sequence is operably joined to an RNA polymerase promoter recognized by the RNA polymerase, so as to obtain a recombinant plasmid, wherein replication level and copy number of said recombinant plasmid in the host cell is regulated by an antisense RNA that is polyadenylated by a poly(A) polymerase encoded by the poly(A) polymerase gene that is operably joined to the conditionally-inducible promoter in said host cell; C. introducing said recombinant plasmid into said host cell; and D. growing said host cell containing said recombinant plasmid that contains said DNA sequence under conditions wherein said conditionally inducible promoter that is operably joined to said poly(A) polymerase gene in said host cell is not induced, wherein the host cell is thereby maintaining said recombinant plasmid at low copy in said host cell under said conditions.