I describe the construction of a variety of Escherichia coli recA deletion strains designed to facilitate molecular cloning. These recA deletion strains permit the efficient cloning of foreign inserts carried in plasmid, phage, cosmid, phasmid (phage-plasmid hybrid) or phosmid (phage-cosmid hybrid) vectors.

Dilution cloning of adherent mammalian cells is a very frequent practice in most molecular and cell biology laboratories. It is commonly used for isolation of specific biochemical mutants, and cell strains with marker chromosomes. In this report, we present a modified and simple dilution cloning method that allows even inexperienced workers to successfully clone adherent mammalian cells.

A familial reciprocal translocation associated with severe macromastia has been characterized by molecular cytogenetic and molecular analysis. Cloning of the translocation breakpoints revealed that no known gene has been disrupted by this translocation. Therefore, a position effect compromising the regulation of a still to be identified gene in the vicinity of the breakpoints can be assumed.

PCR fragments and linear vectors containing overlapping ends are easily assembled into a propagative plasmid by homologous recombination in Escherichia coli. Although this gap-repair cloning approach is straightforward, its existence is virtually unknown to most molecular biologists. To popularize this method, we tested critical parameters influencing the efficiency of PCR fragments cloning int...