d-Fucose as a Gratuitous Inducer of the l-Arabinose Operon in Strains of Escherichia coli B/r Mutant in Gene araC1
AUTOR(ES)
Beverin, Susan
RESUMO
d-Fucose, a nonmetabolizable analogue of l-arabinose, prevents growth of Escherichia coli B/r on a mineral salts medium plus l-arabinose by inhibiting induction of the l-arabinose operon. Mutations giving rise to d-fucose resistance map in gene araC and result in constitutive expression of the l-arabinose operon. Most of these mutations also permit d-fucose to serve as a gratuitous inducer. It is concluded that d-fucose-resistant mutants produce an araC gene product with an altered inducer specificity. Addition of l-arabinose to cells induced with the gratuitous inducer, d-fucose, resulted in severe transient repression of operon expression followed by permanent catabolite repression. Transient repression but no permanent catabolite repression was obtained when cells unable to metabolize l-arabinose were employed. It is concluded that transport of l-arabinose alone is sufficient to achieve transient repression of its own operon, but that metabolism of l-arabinose must occur to achieve permanent catabolite repression of the l-arabinose operon. This general effect has been termed “self-catabolite repression.”
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=246888Documentos Relacionados
- Interaction between mutant alleles of araC of the Escherichia coli B/r L-arabinose operon.
- Dominance relationships among mutant alleles of regulatory gene araC in the Escherichia coli B/R L-arabinose operon.
- Control of Expression of the l-Arabinose Operon in Temperature-Sensitive Mutants of Gene araC in Escherichia coli B/r
- A Second Transport System for l-Arabinose in Escherichia coli B/r Controlled by the araC Gene
- A Second Transport System for l-Arabinose in Escherichia coli B/r Controlled by the araC Gene