Hyaluronic acid synthesis operon (has) expression in group A streptococci
| Autor: | I van de Rijn, Dinene L. Crater |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
DNA
Bacterial Operon Streptococcus pyogenes Molecular Sequence Data Restriction Mapping Hyaluronoglucosaminidase Biology Xenopus Proteins Biochemistry Group A Microbiology chemistry.chemical_compound Hyaluronidase Transferases Hyaluronic acid Extracellular medicine RNA Messenger Glucuronosyltransferase Hyaluronic Acid Molecular Biology Bacterial Capsules Regulation of gene expression Messenger RNA Membranes Base Sequence RNA Glycosyltransferases Membrane Proteins Cell Biology Gene Expression Regulation Bacterial Blotting Northern Molecular biology stomatognathic diseases Blotting Southern chemistry Hyaluronan Synthases medicine.drug |
| Zdroj: | The Journal of biological chemistry. 270(31) |
| ISSN: | 0021-9258 |
| Popis: | The has operon is composed of three genes, hasA, hasB, and hasC that encode hyaluronate synthase, UDP-glucose dehydrogenase, and presumptively UDP-glucose pyrophosphorylase, respectively. Expression of the has operon was shown to be required for the synthesis of the hyaluronic acid capsule in group A streptococci. Previous studies indicated that some group A and group C streptococcal strains produce the hyaluronic acid capsule, while others do not. In addition, it was observed that encapsulated strains cultured in stationary phase of growth lose the hyaluronic acid capsule. Therefore, the molecular mechanisms controlling the expression of the hyaluronic acid capsule in group A streptococci was investigated. In this study, it was determined that all encapsulated and unencapsulated strains of group A streptococci as well as encapsulated group C streptococci analyzed possess the has operon locus. The acapsular phenotype was accounted for by the absence of hyaluronate synthase activity in the membrane and not the production of extracellular hyaluronidase. A has operon mRNA transcript was not expressed by unencapsulated strains of group A streptococci, whereas encapsulated strains of group A streptococci grown to mid to late exponential phase produced the hyaluronate capsule, as well as has operon mRNA. However, as the streptococci entered the stationary phase of growth, they became acapsular and this was concomitant with the loss of has operon mRNA transcript. These results were confirmed by primer extension analyses of RNA isolated from encapsulated and unencapsulated strains of group A streptococci as well as RNA prepared from encapsulated strains cultured in exponential and stationary phases of growth. Thus, the loss of has operon mRNA in unencapsulated group A streptococci, as well as growth phase regulation occurs at the previously mapped has operon promoter. These data suggested that the synthesis of the hyaluronic acid capsule for group A streptococci may be controlled by transcriptional mechanisms. |
| Databáze: | OpenAIRE |
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