TY - JOUR
T1 - Construction and characterization of the chloramphenicol-resistance gene cartridge
T2 - A new approach to the transcriptional mapping of extrachromosomal elements
AU - Close, Timothy J.
AU - Rodriguez, R. L.
PY - 1982
Y1 - 1982
N2 - A system has been developed to transcriptionally map plasmid DNA molecules in vivo. This system is based upon the activity of the Tn 9 Cmr gene whose product, chloramphenicol acetyltransferase (CAT), can be easily assayed enzymatically and identified phenotypically in Escherichia coli. The Cmr gene was excised as a single DNA fragment from the plasmid cloning vector, pBR328, and its ends were converted to hexamer-specific restriction enzyme recognition sites. These modified Cmr gene fragments were designated "CAT cartridges". The CAT cartridges were expressed at high levels only when inserted in the proper orientation, downstream of a plasmid promoter. Using DNA restriction endonuclease cleavage sites as insertion points, the CAT cartridges were inserted into plasmid pBR327, and the levels of CAT activity produced in cells containing the various plasmids were determined. The CAT activities at each position and orientation were used to construct a transcriptional map of plasmid pBR327. The positions and strengths of promoters demonstrated in vivo using the CAT cartridge coincided with those predicted by in vitro studies. Using the CAT cartridges it should be possible to study gene expression on any extrachromosomal element in the appropriate host.
AB - A system has been developed to transcriptionally map plasmid DNA molecules in vivo. This system is based upon the activity of the Tn 9 Cmr gene whose product, chloramphenicol acetyltransferase (CAT), can be easily assayed enzymatically and identified phenotypically in Escherichia coli. The Cmr gene was excised as a single DNA fragment from the plasmid cloning vector, pBR328, and its ends were converted to hexamer-specific restriction enzyme recognition sites. These modified Cmr gene fragments were designated "CAT cartridges". The CAT cartridges were expressed at high levels only when inserted in the proper orientation, downstream of a plasmid promoter. Using DNA restriction endonuclease cleavage sites as insertion points, the CAT cartridges were inserted into plasmid pBR327, and the levels of CAT activity produced in cells containing the various plasmids were determined. The CAT activities at each position and orientation were used to construct a transcriptional map of plasmid pBR327. The positions and strengths of promoters demonstrated in vivo using the CAT cartridge coincided with those predicted by in vitro studies. Using the CAT cartridges it should be possible to study gene expression on any extrachromosomal element in the appropriate host.
KW - pBR327 promoters
KW - readthrough transcription
KW - Tn9 CAT gene
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U2 - 10.1016/0378-1119(82)90048-8
DO - 10.1016/0378-1119(82)90048-8
M3 - Article
C2 - 6299895
AN - SCOPUS:0020362208
VL - 20
SP - 305
EP - 316
JO - Gene
JF - Gene
SN - 0378-1119
IS - 2
ER -