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Cloning and expression of the leukotoxin gene of Pasteurella haemolytica A1 in Escherichia coli K-12.

Abstract：

:A clone bank of Pasteurella haemolytica A1 was constructed by partial digestion of the genomic DNA with Sau3A and ligation of 5- to 10-kilobase-pair fragments into the BamHI site of the plasmid vector pBR322. After transformation into Escherichia coli K-12, a total of 4 X 10(3) recombinant clones was obtained. These were screened for the production of P. haemolytica soluble antigens by a colony enzyme-linked immunosorbent assay blot method with a rabbit antiserum raised against the soluble antigens. The clones producing P. haemolytica soluble antigens were then analyzed for the production of the leukotoxin by a cytotoxicity assay with cells from a bovine leukemia-derived B-lymphocyte cell line as the target cells. Positive clones were identified, and subsequent restriction analysis of the recombinant plasmids showed that the same 6.3 kilobase pairs of insert DNA was cloned in either of the two orientations into the plasmid vector pBR322. One of the clones was selected for further characterization of the leukotoxin as produced in E. coli. Tests for heat lability and target cell species specificity with canine, porcine, and human peripheral blood lymphocytes indicated that the activity of the cloned leukotoxin was identical to that of the P. haemolytica leukotoxin. Furthermore, the E. coli-produced leukotoxin was also neutralized by bovine or rabbit antiserum known to have antitoxic activity. When cellular proteins from the E. coli clones were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis, a 100,000-dalton protein was identified which corresponded to one of the soluble antigens found in the leukotoxic culture supernatant of P. haemolytica. These results demonstrated that the gene(s) for the P. haemolytica leukotoxin have been cloned and that the leukotoxin was expressed in E. coli.

journal_name

Infect Immun

journal_title

Infection and immunity

authors

Lo RY,Shewen PE,Strathdee CA,Greer CN

doi

10.1128/IAI.50.3.667-671.1985

subject

Has Abstract

pub_date

1985-12-01 00:00:00

pages

667-71

issue

eissn

0019-9567

issn

1098-5522

journal_volume

pub_type

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Cloning and expression of the leukotoxin gene of Pasteurella haemolytica A1 in Escherichia coli K-12.