THE STABILITY OF MESSENGER-RNA FROM THE GSIB GENE OF BACILLUS-SUBTILIS IS DEPENDENT ON THE PRESENCE OF A STRONG RIBOSOME BINDING-SITE

In Bacillus subtilis IS58 starved of glucose or exposed to heat shock, ethanol or salt stress, the sigma(B)-dependent general stress protein GsiB is accumulated to a higher level than other general stress prote ins. This high-level accumulation of GsiB can at least partially be at tributed to the remarkably long half-life (similar to 20 min) of the g siB mRNA. Analysis of different gsiB-lacZ fusions revealed that this s tability is not determined by sequences at the 3' end of the transcrip t but rather by sequences upstream of the translational start codon. S ite-directed mutagenesis established that a strong ribosome binding si te was crucial for the increased stability of the gsiB mRNA. A compari son of the sequences upstream of the translational start codons of thr ee general stress genes, gsiB, gspA and ctc, revealed a direct correla tion between mRNA stability and the strength of their translational si gnals.