Previous Article | Next Article ![]()
Journal of Bacteriology, November 1999, p. 6634-6641, Vol. 181, No. 21
Laboratoire de Microbiologie U.A.-INRA,
ENSBANA, 21000 Dijon, France
Received 28 May 1999/Accepted 23 August 1999
Using degenerated primers from conserved regions of previously
studied clpX gene products, we cloned the clpX
gene of the malolactic bacterium Oenococcus oeni. The
clpX gene was sequenced, and the deduced protein of 413 amino acids (predicted molecular mass of 45,650 Da) was highly similar
to previously analyzed clpX gene products from other
organisms. An open reading frame located upstream of the
clpX gene was identified as the tig gene by
similarity of its predicted product to other bacterial trigger factors.
ClpX was purified by using a maltose binding protein fusion system and
was shown to possess an ATPase activity. Northern analyses indicated
the presence of two independent 1.6-kb monocistronic clpX
and tig mRNAs and also showed an increase in
clpX mRNA amount after a temperature shift from 30 to
42°C. The clpX transcript is abundant in the early
exponential growth phase and progressively declines to undetectable
levels in the stationary phase. Thus, unlike hsp18, the
gene encoding one of the major small heat shock proteins of
Oenococcus oeni, clpX expression is related to
the exponential growth phase and requires de novo protein synthesis. Primer extension analysis identified the 5' end of clpX
mRNA which is located 408 nucleotides upstream of a putative AUA start
codon. The putative transcription start site allowed identification of a predicted promoter sequence with a high similarity to the consensus sequence found in the housekeeping gene promoter of gram-positive bacteria as well as Escherichia coli.
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
The Oenococcus oeni clpX Homologue Is a
Heat Shock Gene Preferentially Expressed in Exponential Growth
Phase
*
Corresponding author. Mailing address: Laboratoire de
Microbiologie U.A.-INRA, ENSBANA, 1, esplanade Erasme, 21000 Dijon, France. Phone: (33) 3 80 39 66 75. Fax: (33) 3 80 39 66 40. E-mail: jguzzo{at}u-bourgogne.fr.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»