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Mol Microbiol

Title:		Regulation of the Enterococcus faecalis pAD1-related sex pheromone response: analyses of traD expression and its role in controlling conjugation functions
Author(s):		do Carmo de Freire Bastos; Tomita H; Tanimoto K; Clewell DB;
Address:		"Department of Biologic and Materials Sciences, School of Dentistry, The University of Michigan, Ann Arbor, MI 48109-1078, USA"
Journal Title:		Mol Microbiol
Year:		1998
Volume:		30
Issue:		2
Page Number:		381 - 392
DOI:		10.1046/j.1365-2958.1998.01074.x
ISSN/ISBN:		0950-382X (Print) 0950-382X (Linking)
Abstract:		"The Enterococcus faecalis haemolysin plasmid pAD1 (60 kb) confers a conjugative mating response to an octapeptide sex pheromone (cAD1) secreted by plasmid-free strains. The response involves two plasmid-borne regulatory determinants: traE1, whose product positively regulates all or most conjugation-related structural genes; and traA, whose product negatively regulates traE1 by controlling transcriptional readthrough of an upstream termination site (TTS1/TTS2). TraA binds to the promoter region of iad, which encodes a pheromone-inhibitor peptide, iAD1; and TTS1/TTS2 tightly terminates transcription arriving from this promoter during the uninduced state. A determinant, traD, appearing to encode a small peptide (23 amino acids), is located just downstream of iad and is in the opposite orientation. Transcripts of traD were identified and found to be present at a relatively high level in cells not expressing conjugation functions; the amount of RNA was greatly reduced, however, upon induction of the pheromone response. The decrease in traD RNA was not a consequence of the induced activity of TraE1, as it also occurred in a traE1 insertion mutant. A mutation in traD that would eliminate translation but that did not affect transcription had no apparent effect on the cell phenotype, indicating that RNA was likely to be the functional product. This was consistent with our finding that synthesis of traD RNA containing the translational defect was able to complement, in trans, a temperature-sensitive traD mutation. Thus, transcription of the traD determinant is significantly involved in downregulation of the pAD1 pheromone response"
Keywords:		"Amino Acid Sequence Bacterial Proteins/*genetics/metabolism Base Sequence DNA Transposable Elements Enterococcus faecalis/drug effects/*genetics/*metabolism *Escherichia coli Proteins Gene Expression Regulation, Bacterial Hemolysin Factors/*genetics/metab;"
Notes:		"Medlinedo Carmo de Freire Bastos, M Tomita, H Tanimoto, K Clewell, D B eng GM33956/GM/NIGMS NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. England 1998/10/29 Mol Microbiol. 1998 Oct; 30(2):381-92. doi: 10.1046/j.1365-2958.1998.01074.x"