| 摘要 |
(1) Vector that on introduction into a suitable bacterial host cell contg. the thermolabile repressor C (I) renders the host cell capable, when the temp. is raised to a level at which the repressor is inactivated, of effecting expression of a desired gene inserted in the vector to produce polypeptide (I) encoded by the gene is new when it comprises a double-stranded DNA molecule including in 5'- to 3'- order. (a) DNA sequence contg. the promoter and operator P(L)O(L) from lambda bacteriophage; (b) a N utilisation site for binding antiterminator N protein; (c) a first restriction enzyme site permitting replacement of the DNA sequence contg. the ribosomal binding site following after; (d) DNA sequence contg. a ribosomal binding site for making the MRNA of the desired gene capable of binding to ribosomes in the host cell; (e) ATG initiator codon or a DNA sequence converted into the codon on insertion of the desired gene into the vector; and (f) a second restriction enzyme site for inserting the desired gene into the vector in phase with the ATG initiation codon; and (g) a DNA sequence contg. an origin of replication from a bacterial plasmid capable of autonomous replication in the host cell; and for selection, DNA sequence contg. a gene associated with a selectable or identifiable phenotypic trait manifested when the vector is present in the host cell, or DNA sequence contg. fragment C (I) 434, including the gene for the C (I) 434 repressor protein and its associated promoter and operator sequence. |
