A simplified method for mapping deletion/substitution mutants of bacteriophage lambda

A detailed comparison of the 5'-end of the ovalbumin gene cloned from chicken oviduct and erythrocyte DNA

We have examined homologous fragments of DNA cloned from two different tissues for changes in the dNA sequence which might be related to tissue specific gene expression. The 5' end of the chicken ovalbumin gene was cloned from oviduct or erythrocyte DNA DNA using cosmids as vectors. We have compared the two clones obtained by restriction enzyme digestions, analysis of heteroduplexes by electron microscopy or S1 nuclease digestion and by DNA sequencing. Our results show that whereas no alteration occured in the region of the gene assumed to be of importance for the control of transcription, a 4 nucleotide deletion/insertion was detected in the first intron of the ovalbumin gene.

Isolation and characterization of a ColE1 plasmid containing the entire bio gene cluster of Escherichia coli K12

ColE1amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1amp as the cloning vehicle and a lambda transducing phage, lambdaatt2, as the source of bio DNA. Restriction endonuclease EcoRI digests of ColE1amp and lambdaatt2 DNA were joined by polynucleotide ligase and plasmids bearing the entire bio gene cluster were selected, after transformation, in bio deletion strains of E. coli. Recombinant DNA molecules contained one ColE1amp fragment (7.4 X 10(6) daltons) and one lambdaatt2 DNA fragment (5.4 X 10(6) daltons). Clones carrying ColE1 amp-bio plasmids produce elevated levels of biotin and biotin synthetase activity.