A method for producing a recombinant baculovirus expression vector, capable of expression of a selected gene in a host insect cell, is disclosed. The preferred method involves cleaving baculovirus DNA to produce a DNA fragment comprising a polyhedrin gene or portion thereof, including a polyhedrin promoter. A recombinant shuttle vector is prepared by inserting said DNA fragment into a cloning vehicle and thereafter inserting a selected gene into the thus modified cloning vehicle such that it is under the transcriptional control of the polyhedrin promoter. The recombinant shuttle vector is contacted with a baculovirus DNA so as to effect recombination and incorporation of the selected gene into the baculovirus genome.

A synthetic gene characterised in that it codes for the expression of urogastrone or a sub-unit thereof is disclosed. The production thereof by the assembly and ligation of a number of nucleotide blocks is also disclosed, as are corresponding plasmid recombinants, transformed cells and the production thereof. The expression of urogastrone is further disclosed. Urogastrone is a polypeptide hormore (protein) which may be isolated in small amounts from human urine. It has an application in the treatment of ulcers and in the promotion of wound healing. The present invention provides a more viable commercial production.

A method for producng a recombinant baculovirus expression vector, capable of expressing a selected gene in a host insect cell, is disclosed. The method involves cleaving baculovirus DNA to produce a DNA fragment comprising a polyhedrin gene or portion thereof, including a polyhedrin promoter. A recombinant transfer vector is prepared by inserting said DNA fragment into a cloning vehicle and thereafter inserting a selected gene into the thus modified cloning vehicle such that it is under the transcriptional control of the polyhedrin promoter. The recombinant transfer vector is contacted with a baculovirus DNA so as to effect recombination and incorporation of the selected gene into the baculovirus genome. The resultant recombinant baculovirus is then used to infect susceptible insects or cultured insect cells and the protein product from the incorporated selected gene is produced from the infection.

DNA encoding a novel polypeptide hormone, designated CTP, has been identified in the human genome. CTP is expressed as a fusion protein (proLHRH) with luteinizing hormone releasing hormone (LHRH), and is post-translationally processed to CTP and LHRH. CTP, its derivatives, and its fusions, including proLHRH, are useful in therapy and diagnostics.

DNA plasmids are described which are selected mutants in which an altered repressor gene leads to high copy number replication. Elements in the plasmids are modified in such a way that readthrough expression of heterologous DNA inserted in the plasmid will not continue into the replication primer strand. Deletions resulting from interference with replication primer strand transcription are thereby avoided.