L. Fang et al., PROMOTER-INDEPENDENT COLD-SHOCK INDUCTION OF CSPA AND ITS DEREPRESSION AT 37-DEGREES-C BY MESSENGER-RNA STABILIZATION, Molecular microbiology, 23(2), 1997, pp. 355-364
The gene for CspA, the major cold-shock protein of Escherichia coli is
known to be dramatically induced upon temperature downshift. Here, we
report that three-base substitutions around the Shine-Dalgarno sequen
ce in the 159-base 5'-untranslated region of the cspA mRNA stabilizes
the mRNA 150-fold, resulting in constitutive expression of cspA at 37
degrees C. This stabilization was found to be at least partially due t
o resistance against RNase E degradation. The cold-shock induction of
cspA was also achieved by exchanging its promoter with the non-cold-sh
ock Ipp promoter. The results presented indicate that the cspA gene is
efficiently transcribed even at 37 degrees C. However, the translatio
n of the cspA mRNA is blocked because of its extreme instability at 37
degrees C. The presented results also demonstrate that the cspA gene
is constitutively transcribed at all temperatures; however, its expres
sion at 37 degrees C is prevented by destabilizing its mRNA.