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Identification of isp, a locus encoding an immunogenic secreted protein conserved among group A streptococci.
- Source :
-
Infection and immunity [Infect Immun] 1996 Jul; Vol. 64 (7), pp. 2548-55. - Publication Year :
- 1996
-
Abstract
- The protein Mga (mga), which is required for transcription of several virulence genes of group A streptococci (GAS), including the antiphagocytic M protein, was suggested to act as the response regulator element of a bacterial two-component pathway. To investigate whether a gene encoding a cognate sensor protein is located upstream of mga, 3.1 kb of DNA 5' of the mga translational start site was cloned from serotype M6 GAS strain JRS4. Sequence analysis of this region revealed two adjacent open reading frames, a previously described orf and a new locus, isp (immunogenic secreted protein), which could encode proteins of 9 and 59 kDa, respectively. Inactivation of either open reading frame had no significant effect on transcription of the gene encoding M protein (emm) under normal growth conditions, suggesting that neither isp nor orf is involved in the Mga regulatory circuit. A protein migrating at an apparent molecular weight of 65,000 was produced when isp was transcribed and translated in vitro. The predicted isp product (Isp) contains an amino-terminal signal sequence region homologous to that found in bacterial secreted proteins, and expression of isp in Escherichia coli resulted in the presence of Isp in the periplasmic fraction. Convalescent-phase serum from a patient with an active GAS infection recognized forms of Isp both from the periplasm of E. coli and the supernatant of a GAS strain. Both isp and orf are highly conserved among strains of GAS, as shown by hybridization analyses.
- Subjects :
- Amino Acid Sequence
Bacterial Proteins metabolism
Base Sequence
Conserved Sequence
DNA Primers genetics
DNA, Bacterial genetics
Molecular Sequence Data
Molecular Weight
Sequence Homology, Amino Acid
Transcription Factors genetics
Bacterial Proteins genetics
Bacterial Proteins immunology
Genes, Bacterial
Streptococcus pyogenes genetics
Streptococcus pyogenes immunology
Subjects
Details
- Language :
- English
- ISSN :
- 0019-9567
- Volume :
- 64
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Infection and immunity
- Publication Type :
- Academic Journal
- Accession number :
- 8698478
- Full Text :
- https://doi.org/10.1128/iai.64.7.2548-2555.1996