title: Tn7-encoded proteins.
abstract: Proteins encoded by Tn7 have been studied in Escherichia coli maxicells harbouring either various deleted ColE1::Tn7 plasmids or Tn7 fragments cloned in pBR322. Six Tn7-encoded proteins were detected and named p18, p32, p40, p54, p85-a and p85-b according to their apparent molecular weight. Protein p18 is dihydrofolate reductase type I and p32 is probably the protein conferring resistance to streptomycin/spectinomycin. Both genes map on the left-hand part of Tn7. The genes for the four other proteins are located on the right-hand part of Tn7. We propose that they fully cover a 6.9 kb DNA fragment without any overlapping. Starting from the right-hand end towards the middle of the transposon, these four genes are in the following order: p85-a, p54, p40 and p85-b. Transposition of Tn7 onto E. coli plasmids requires the proteins p85-a, p85-b, p54 and p40. However, transposition onto the chromosome does not require the p85-b and p40 products.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D005838:Genotype; D008970:Molecular Weight; D010957:Plasmids; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D004262:DNA Restriction Enzymes