A physical map of group A streptococcal bacteriophage T12 was constructed with restriction endonucleases Sal/I, PstI, and EcoRI. The map is circularly permuted with a total length of 36.0 kb. Sub-molar quantities of certain restriction fragments, some of very precise MW and some of heterogeneous MW,
Group A streptococcal phage T12 carries the structural gene for pyrogenic exotoxin type A
โ Scribed by Johnson, Lane P. ;Schlievert, Patrick M.
- Publisher
- Springer
- Year
- 1984
- Tongue
- English
- Weight
- 561 KB
- Volume
- 194
- Category
- Article
- ISSN
- 0026-8925
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โฆ Synopsis
The structural gene for group A streptococcal pyrogenic exotoxin (SPE) type A was cloned into E. coli. DNA fragments used for cloning the toxin gene were isolated from bacteriophage T12. Toxin, present in cell lysates of E. coli clones, immunoprecipitated with antisera raised against purified SPE type A and formed a line of identity with streptococcal-derived A toxin. The cloned toxin shared the following biological activities with streptococcal A toxin: Pyrogenicity; enhancement of host susceptibility to lethal endotoxin shock; nonspecific lymphocyte mitogenicity; and alteration of immunoglobulin production. The physical location of the toxin gene on the phage T12 genome was determined.
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The M protein gene (emm gene) from a reference group A streptococcal strain of serotype M3 was amplified by the polymerase chain reaction and partially sequenced. Hybridization assays using an oligonucleotide probe derived from the N-terminal sequence revealed that this gene segment is highly homolo