Pheromone-Regulated Expression of Sex Pheromone Plasmid pAD1-Encoded Aggregation Substance Depends on at Least Six Upstream Genes and a cis -Acting, Orientation-Dependent Factor
| Autor: | Albrecht Muscholl-Silberhorn |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Genetic Vectors
Molecular Sequence Data Regulator Genetics and Molecular Biology Regulatory Sequences Nucleic Acid Biology Microbiology Pheromones Plasmid Bacterial Proteins Enterococcus faecalis Adhesins Bacterial Promoter Regions Genetic Molecular Biology Psychological repression Gene Genetics Reporter gene Membrane Proteins Gene Expression Regulation Bacterial Genes Bacterial Sex pheromone Pheromone Fimbriae Proteins Trans-acting alpha-Amylases Plasmids |
| Zdroj: | Journal of Bacteriology. 182:3816-3825 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.182.13.3816-3825.2000 |
| Popis: | Conjugative transfer of Enterococcus faecalis -specific sex pheromone plasmids relies on an adhesin, called aggregation substance, to confer a tight cell-to-cell contact between the mating partners. To analyze the dependence of pAD1-encoded aggregation substance, Asa1, on pheromone induction, a variety of upstream fragments were fused to an α-amylase reporter gene, amyL , by use of a novel promoter probe vector, pAMY-em1. For pheromone-regulated α-amylase activity, a total of at least six genes, traB , traC , traA , traE1 , orfY , and orf1 , are required: TraB efficiently represses asa1 (by a mechanism unrelated to its presumptive function in pheromone shutdown, since a complete shutdown is observed exclusively in the presence of traC ); only traC can relieve traB -mediated repression in a pheromone-dependent manner. In addition to traB , traA is required but not sufficient for negative control. Mutational inactivation of traE1 , orfY , or orf1 , respectively, results in a total loss of α-amylase activity for constructs normally mediating constitutive expression. Inversion of a fragment covering traA , P 0 , and traE1 without disrupting any gene or control element switches off amyL or asa1 expression, indicating the involvement of a cis -acting, orientation-dependent factor (as had been shown for plasmid pCF10). Unexpectedly, pAD1 represses all pAMY-em1 derivatives in trans , while its own pheromone-dependent functions are unaffected. The discrepancy between the new data and those of former studies defining TraE1 as a trans -acting positive regulator is discussed. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|