JB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Serrano, M.
Right arrow Articles by Henriques, A. O.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Serrano, M.
Right arrow Articles by Henriques, A. O.

Journal of Bacteriology, June 1999, p. 3632-3643, Vol. 181, No. 12
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.

A Bacillus subtilis Secreted Protein with a Role in Endospore Coat Assembly and Function

Mónica Serrano,1,2 Rita Zilhão,2 Ezio Ricca,3 Amanda J. Ozin,4 Charles P. Moran Jr.,4,* and Adriano O. Henriques1,4

Instituto de Tecnologia Química e Biológica, 2780 Oeiras Codex,1 and Centro de Genética e Biologia Molecular, Universidade de Lisboa, Campo Grande C2, 1700 Lisbon,2 Portugal; Department of General and Environmental Physiology, Federico II University, 80134 Naples, Italy3; and Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 303224

Received 8 February 1999/Accepted 9 April 1999

Bacterial endospores are encased in a complex protein coat, which confers protection against noxious chemicals and influences the germination response. In Bacillus subtilis, over 20 polypeptides are organized into an amorphous undercoat, a lamellar lightly staining inner structure, and an electron-dense outer coat. Here we report on the identification of a polypeptide of about 30 kDa required for proper coat assembly, which was extracted from spores of a gerE mutant. The N-terminal sequence of this polypeptide matched the deduced product of the tasA gene, after removal of a putative 27-residue signal peptide, and TasA was immunologically detected in material extracted from purified spores. Remarkably, deletion of tasA results in the production of asymmetric spores that accumulate misassembled material in one pole and have a greatly expanded undercoat and an altered outer coat structure. Moreover, we found that tasA and gerE mutations act synergistically to decrease the efficiency of spore germination. We show that tasA is the most distal member of a three-gene operon, which also encodes the type I signal peptidase SipW. Expression of the tasA operon is enhanced 2 h after the onset of sporulation, under the control of sigma H. When tasA transcription is uncoupled from sipW expression, a presumptive TasA precursor accumulates, suggesting that its maturation depends on SipW. Mature TasA is found in supernatants of sporulating cultures and intracellularly from 2 h of sporulation onward. We suggest that, at an early stage of sporulation, TasA is secreted to the septal compartment. Later, after engulfment of the prespore by the mother cell, TasA acts from the septal-proximal pole of the spore membranes to nucleate the organization of the undercoat region. TasA is the first example of a polypeptide involved in coat assembly whose production is not mother cell specific but rather precedes its formation. Our results implicate secretion as a mechanism to target individual proteins to specific cellular locations during the assembly of the bacterial endospore coat.

* Corresponding author. Mailing address: Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322. Phone: (404) 727-5969. Fax: (404) 727-3659. E-mail: moran{at}microbio.emory.edu.

Journal of Bacteriology, June 1999, p. 3632-3643, Vol. 181, No. 12
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
Appl. Environ. Microbiol. Infect. Immun. Eukaryot. Cell
Mol. Cell. Biol. J. Virol. Microbiol. Mol. Biol. Rev.
ALL ASM JOURNALS

Copyright © 1999 by the American Society for Microbiology. All rights reserved.