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Journal of Bacteriology, August 2000, p. 4414-4424, Vol. 182, No. 16
Institut de Génétique et
Microbiologie, Université Paris XI, 91405 Orsay Cedex,
France,1 and Institut für
Genetik, Ludwig Maximilians Universität, 80638 Munich,
Germany2
Received 7 February 2000/Accepted 26 May 2000
The lrpC gene was identified during the Bacillus
subtilis genome sequencing project. Previous experiments
suggested that LrpC has a role in sporulation and in the regulation of
amino acid metabolism and that it shares features with
Escherichia coli Lrp, a transcription regulator (C. Beloin, S. Ayora, R. Exley, L. Hirschbein, N. Ogasawara, Y. Kasahara, J. C. Alonso, and F. Le Hégarat, Mol. Gen. Genet.
256:63-71, 1997). To characterize the interactions of LrpC with DNA,
the protein was overproduced and purified. We show that LrpC binds to
multiple sites in the upstream region of its own gene with a stronger
affinity for a region encompassing P1, one of the
putative promoters identified (P1 and P2). By
analyzing lrpC-lacZ transcriptional fusions, we
demonstrated that P1 is the major in vivo promoter and
that, unlike many members of the lrp/asnC family,
lrpC is not negatively autoregulated but rather slightly
positively autoregulated. Production of LrpC in vivo is low in both
rich and minimal media (50 to 300 LrpC molecules per cell). In rich
medium, the cellular LrpC content is six- to sevenfold lower during the
exponentional phase than during the stationary growth phase. Possible
determinants and the biological significance of the regulation of
lrpC expression are discussed.
0021-9193/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Characterization of LrpC DNA-Binding Properties and Regulation
of Bacillus subtilis lrpC Gene Expression

*
Corresponding author. Mailing address: Institut de
Génétique et Mikrobiologie, Université Paris
XI, Bât. 409, 91405 Orsay Cedex, France. Phone: 33 1 69 15 63 62. Fax: 33 1 69 15 78 08. E-mail:
Francoise.Le-Hegarat{at}igmors.u-psud.fr.
Present address: Moyne Institute of Preventive Medicine, Department
of Microbiology, Trinity College, Dublin 2, Republic of Ireland.
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