Evidence for the expression of native Mycobacterium tuberculosis phospholipase C: recognition by immune sera and detection of promoter activity
Braz. j. med. biol. res
;
33(11): 1275-82, Nov. 2000. ilus, tab
Article
in English
| LILACS
| ID: lil-273222
ABSTRACT
The genome of Mycobacterium tuberculosis H37Rv contains three contiguous genes (plc-a, plc-b and plc-c) which are similar to the Pseudomonas aeruginosa phospholipase C (PLC) genes. Expression of mycobacterial PLC-a and PLC-b in E. coli and M. smegmatis has been reported, whereas expression of the native proteins in M. tuberculosis H37Rv has not been demonstrated. The objective of the present study was to demonstrate that native PLC-a is expressed in M. tuberculosis H37Rv. Sera from mice immunized with recombinant PLC-a expressed in E. coli were used in immunoblots to evaluate PLC-a expression. The immune serum recognized a 49-kDa protein in immunoblots against M. tuberculosis extracts. No bands were visible in M. tuberculosis culture supernatants or extracts from M. avium, M. bovis and M. smegmatis. A 550-bp DNA fragment upstream of plc-a was cloned in the pJEM12 vector and the existence of a functional promoter was evaluated by detection of ß-galactosidase activity. ß-Galactosidase activity was detected in M. smegmatis transformed with recombinant pJEM12 grown in vitro and inside macrophages. The putative promoter was active both in vitro and in vivo, suggesting that expression is constitutive. In conclusion, expression of non-secreted native PLC-a was demonstrated in M. tuberculosis
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Type C Phospholipases
/
Promoter Regions, Genetic
/
Immune Sera
/
Mycobacterium tuberculosis
Type of study:
Diagnostic study
Limits:
Animals
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
2000
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
Universidade Federal de Säo Paulo/BR
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