Expression vector for enhanced polypeptide prodn. by host

摘要

Vector comprises the following (a) a double-stranded DNA molecule including in 5' to 3' order the following: DNA sequence contg. the promoter and operator PLOL from lambda bacteriophage; the N utilisation site for binding antiterminator N protein produced by the host cell; DNA sequence contg. a ribosomal binding site for rendering the mRNA of the desired gene capable of binding to ribosomes within the host cell; ATC initiation codon or DNA sequence that is converted to an ATG initiation codon on insertion of the desired gene into the vector; and a restriction enzyme site for insertion of the desired gene into the vector and in phase with the ATG initiation codon; and (b) a DNA sequence contg. an origin of replication from a bacterial plasmid capable of autonomous replication in the host cell and a DNA sequence contg. a gene associated with a selectable or identifiable phenotypic trait manifested when the vector is present in the host cell. - Plasmid for prodn of a polypeptide (I) comprising a vector as defined above and a gene encoding the (I) or its analogue inserted into the restriction enzyme site is new. Host vector system for prodn. of (I) comprising a plasmid as defined above is new. Bovine growth hormone (BGH) analogue having the activity of naturally occurring BGH and a similar amino acid sequence varying from the sequence of natural BGH by up to 5 amino acids at the N-terminus is new. Human growth hormone (HGH) analogue having the activity of naturally occurring HGH and a similar amino acid sequence varying from the sequence of natural HGH is new.