U. Sauer et P. Durre, SEQUENCE AND MOLECULAR CHARACTERIZATION OF A DNA REGION ENCODING A SMALL HEAT-SHOCK PROTEIN OF CLOSTRIDIUM-ACETOBUTYLICUM, Journal of bacteriology, 175(11), 1993, pp. 3394-3400
A DNA region of Clostridium acetobutylicum containing a gene (hsp18) w
ith significant homology to a family of small eukaryotic heat shock pr
oteins was cloned and sequenced. It is the second reported sequence of
a low-molecular-weight heat shock protein from gram-positive bacteria
and is induced not only by heat shock but also at the onset of solven
togenesis, as determined by Northern (RNA) blot analysis, thus confirm
ing the results of an earlier study performed at the protein level (A.
Pich, F. Narberhaus, and H. Bahl, Appl. Microbiol. Biotechnol. 33:697
-704, 1990). By primer extension analysis, a transcriptional start sit
e was identified 149 bp upstream of hsp]8. This site was preceded by a
region that exhibits high homology to the consensus promoter sequence
s of gram-positive bacteria, as well as sigma70-dependent Escherichia
coli. A direct repeat structure was detected in the -35 region. The pr
omoter is located 196 bp from the start of a potential regulatory tRNA
(ACG)Thr. gene involved in the shift to solventogenesis which is trans
cribed in the opposite direction. A putative rho-independent transcrip
tion termination structure was identified at the 3' end of hsp18.