ANTISENSE RNA REGULATION OF THE FATB IRON TRANSPORT PROTEIN GENE IN VIBRIO-ANGUILLARUM

We have recently identified an antisense RNA (RNA alpha) that regulate s the expression of the fatA iron transport gene encoding the outer me mbrane receptor for. the iron-anguibactin complex. In this work, we de monstrate that RNA alpha also inhibits the expression of fatB, which e ncodes a 35 kDa iron transport protein and has domains homologous to o ther periplasmic transport proteins. The expression of fatA and fatB i s repressed under iron-rich conditions, in which RNA alpha is induced. RNA alpha is homologous to two-thirds of the coding region of fatB. B y cloning RNA alpha coding sequences immediately downstream of a tet p romoter, we were able to obtain constitutive expression of the antisen se RNA. The cloned region contains approximately 83% of the 650 nucleo tide RNA alpha and is complementary to only 51% of the fatB mRNA but i s still capable of causing a repression of the expression of the fatB gene. Our results in this work demonstrate that RNA alpha probably aff ects the stability of the fatB-specific mRNA.