DELETION ANALYSIS OF CSPA OF ESCHERICHIA-COLI - REQUIREMENT OF THE AT-RICH UP ELEMENT FOR CSPA TRANSCRIPTION AND THE DOWNSTREAM BOX IN THE CODING REGION FOR ITS COLD SHOCK INDUCTION
M. Mitta et al., DELETION ANALYSIS OF CSPA OF ESCHERICHIA-COLI - REQUIREMENT OF THE AT-RICH UP ELEMENT FOR CSPA TRANSCRIPTION AND THE DOWNSTREAM BOX IN THE CODING REGION FOR ITS COLD SHOCK INDUCTION, Molecular microbiology, 26(2), 1997, pp. 321-335
In order to analyse the mechanism of cold shock induction of CspA, a m
ajor cold shock protein of Escherichia coli, deletion analysis of the
cspA gene was carried out. It was found that (i) the AT-rich sequence
(-47 to -38) upstream of the cspA -35 region may act as the UP element
playing a crucial role in cspA transcription at both 37 degrees C and
15 degrees C; (ii) the unusually long 5'-UTR of the cspA mRNA has neg
ative effects on cspA expression at 37 degrees C; and (iii) in contras
t, the 5'-UTR exerts a positive effect on mRNA stabilization at low te
mperature. Furthermore, it was demonstrated that the 14 base downstrea
m box (DB) locating 12 bases downstream of the initiation codon of the
cspA mRNA and complementary to a region near the decoding region of 1
6S rRNA was essential for the mRNA translation during the growth lag a
cclimation phase immediately after cold shock. During this phase, tran
slation of non-cold shock gene mRNAs is blocked, since they require co
ld shock-specific ribosomal factors for the formation of the translati
on initiation complex. It is proposed that DB in cold shock mRNAs allo
ws the formation of a stable initiation complex at low temperature in
the absence of the cold shock ribosomal factors.