Previous Article | Next Article ![]()
Journal of Bacteriology, February 1999, p. 1118-1125, Vol. 181, No. 4
Department of Biology, Indiana University,
Bloomington, Indiana 47405-6801
Received 3 June 1998/Accepted 10 December 1998
Attachment to surfaces by the prosthecate bacterium
Caulobacter crescentus is mediated by an adhesive
organelle, the holdfast, found at the tip of the stalk. Indirect
evidence suggested that the holdfast first appears at the swarmer pole
of the predivisional cell. We used fluorescently labeled lectin and
transmission electron microscopy to detect the holdfast in different
cell types. While the holdfast was readily detectable in stalked cells
and at the stalked poles of predivisional cells, we were unable to
detect the holdfast in swarmer cells or at the flagellated poles of
predivisional cells. This suggests that exposure of the holdfast to the
outside of the cell occurs during the differentiation of swarmer to
stalked cells. To investigate the timing of holdfast synthesis and
exposure to the outside of the cell, we have examined the regulation of a holdfast attachment gene, hfaA. The hfaA gene
is part of a cluster of four genes (hfaABDC), identified in
strain CB2A and involved in attachment of the holdfast to the polar
region of the cell. We have identified the hfaA gene in the
synchronizable C. crescentus strain CB15. The sequence of
the CB2A hfaA promoter suggested that it was regulated by
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Cell Cycle Control of a Holdfast Attachment Gene in
Caulobacter crescentus
54. We show that the transcription of hfaA
from either strain is not dependent on
54. Using a
hfaA-lacZ fusion, we show that the transcription of hfaA is temporally regulated during the cell cycle, with
maximal expression in late-predivisional cells. This increase in
expression is largely due to the preferential transcription of
hfaA in the swarmer pole of the predivisional cell.
*
Corresponding author. Mailing address: Department of
Biology, JH142, Indiana University, Bloomington, IN 47405-6801. Phone: (812) 855-8860. Fax: (812) 855-6705. E-mail:
ybrun{at}bio.indiana.edu.
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»