Abstract: The invention relates to modifying plasmid origins of replication to create hybrid origins of replication containing nucleotide sequences from more than one plasmid. The invention also relates to a modified origin of replication cassette that is portable or exchangeable due to the creation of multiple cloning sites flanking the origin of replication. Methods and plasmids for use in exchanging origins of replication are disclosed. Such modified or hybrid plasmids provide useful cloning tools that allow for regulation of the level of expression of a desired protein.

Abstract: The instant invention is drawn to the methods and compositions necessary to provide recombinant proteins with a substantially reduced or eliminated content of norleucine or other non-standard amino acids. Various embodiments of the invention provide for the substantial elimination of the incorporation of non-standard amino acids into recombinant proteins by the co-expression or enhanced expression of a protein (or the enzymatically active portion thereof) capable of degrading norleucine or other non-standard amino acids, including norvaline, beta-methylnorleucine, and homoisoleucine. In certain particular embodiments of the invention, the norleucine is degraded by a glutamate dehydrogenase, a leucine dehydrogenase, a valine dehydrogenase, a phenylalanine dehydrogenase, a glutamate/leucine/phenylalanine/valine dehydrogenase, or an opine dehydrogenase. Also provided are the cells and DNA constructs for carrying out these methods.

Abstract: The invention relates to modifying plasmid origins of replication to create hybrid origins of replication containing nucleotide sequences from more than one plasmid. The invention also relates to a modified origin of replication cassette that is portable or exchangeable due to the creation of multiple cloning sites flanking the origin of replication. Methods and plasmids for use in exchanging origins of replication are disclosed. Such modified or hybrid plasmids provide useful cloning tools that allow for regulation of the level of expression of a desired protein.

Abstract: A family of somatotropin vectors with which micro-organisms, preferably bacteria such as, but not limited to E. coli, can be transformed to enable the expression of bovine somatotropin at high levels using conventional fermentation and induction conditions.

Abstract: A heterologous polypeptide is expressed under the control of a DNA construct containing a promoter region derived from a cyanophage or cyanobacteria promoter. In one embodiment, such a promoter region is operably linked to an operator region derived from an operator native to the host cell. In another embodiment, the operator region is positioned upstream of the promoter region.

Abstract: A family of somatotropin vectors with which micro-organisms, preferably bacteria such as, but not limited to E. coli, can be transformed to enable the expression of bovine somatotropin at high levels using conventional fermentation and induction conditions.

Abstract: A composition for expression of a protein-encoding gene in a host cell is described, making use of an heterologous regulon. This composition provides a protein-encoding gene under control of a promoter heterologous to the host cell, and a gene for an RNA polymerase, preferably a single-subunit RNA polymerase that recognizes the promoter heterologous to the host cell. The gene for the RNA polymerase is under control of an inducible promoter recognized by the host cell. Also disclosed is a method for expressing the protein-encoding gene using the composition described.