Bacteriophage lambda-E. coli K12 vector-host system for gene cloning and expression under lactose promoter control: I. DNA fragment insertion at the lacZ EcoRI restriction site

Bacteriophage lambda vectors, derived from lambda plac5 were constructed. Their genomes have only one EcoRI restriction site, located near the end of the beta-galactosidase gene. Recombinants, constructed in vitro, having a DNA fragment inserted in the EcoRI site, are lac- and can be easily recognized. Expression of such foreign genes is then under the control of the lac promoter. Mutations Qam73 and Sam7 greatly increase the amount of beta-galactosidase synthesized by the vector bacteriophage. The lambda ZEQS vector has been certified B2 (EK2) by the French control commission "Recombinaisons génétiques in vitro".

Localization of Streptomyces stanfordii endonuclease I (SstI) cleavage sites on genomes of human adenovirus types two and five

The SstI restriction endonuclease cleaves adenovirus 2 and 5 (Ad2 and Ad5) DNAs into 15 and 16 fragments, respectively. Cleavage sites were positioned with respect to several other cuts made by seven restriction endonucleases. There are relatively few SstI sites in the middle portion and in the right side of the genome, while several are located within the 16.5--20% region which contains "leader sequences".

[Cloning of the hepatitis B virus genome in Escherichia coli]

The whole genome of the hepatitis B virus (Dane particles) was inserted in vitro in the genome of the bacteriophage lambda gtWES . LAMBDA B. The recombinant DNA molecule was cloned in E. coli. Amplification of the hybrid bacteriophage enables the preparation of large amounts of hepatitis B virus DNA. The possibilities offered by the utilization of this recombinant bacteriophage are discussed.