| 摘要 |
A plasmid cloning vector containing both transcriptional and translational regulatory sequences derived from the bacteriophage lambda genome was constructed to achieve high level expression of prokaryotic and eukaryotic genes. The system utilizes a plasmid vehicle carrying the strong, regulatable lambda promoter, PL, and host lysogens into which this vector can be stabily transformed. The lysogen synthesizes sufficient repressor (cI) to control PL expression and thereby stabilize plasmids which carry such a highly efficient promoter. Use of a temperature sensitive repressor permits simple, rapid induction of PL transcripts at any given time. Efficient transcription of essentially any coding sequence is assured by providing the phage lambda antitermination factor, N, and a site on the transcription unit for its utilization (Nut site). This pAS1 plasmid closely resembles the earlier constructed pKC30cII, also a regulatory protein which activates promoters for lysogenic development.
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