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J Bacteriol

Title:		"Regulation of transfer of the Enterococcus faecalis pheromone-responding plasmid pAD1: temperature-sensitive transfer mutants and identification of a new regulatory determinant, traD"
Author(s):		de Freire Bastos MC; Tanimoto K; Clewell DB;
Address:		"Department of Biologic and Materials Sciences, School of Dentistry, The University of Michigan, Ann Arbor 48109, USA"
Journal Title:		J Bacteriol
Year:		1997
Volume:		179
Issue:		10
Page Number:		3250 - 3259
DOI:		10.1128/jb.179.10.3250-3259.1997
ISSN/ISBN:		0021-9193 (Print) 1098-5530 (Electronic) 0021-9193 (Linking)
Abstract:		"The enterococcal, conjugative, cytolysin plasmid pAD1 confers a mating response to the peptide sex pheromone cAD1 secreted by plasmid-free strains of Enterococcus faecalis. Cells carrying pAM714, a pAD1::Tn917 derivative with wild-type conjugation properties, were mutagenized with ethyl methanesulfonate to obtain variants that were induced (in the absence of pheromone) to transfer plasmid DNA upon shifting from 32 to 42 degrees C. Of 31 such mutants generated, the results of analyses of 7 are presented in detail. All seven strains were thermosensitive in the E. faecalis host FA2-2; colony morphology, clumping, and DNA transfer correlated well with each other at the two temperatures. In the nonisogenic host E. faecalis OG1X, however, only one derivative (pAM2725) exhibited correlation of all three traits at both temperatures. Three (pAM2700, pAM2703, and pAM2717) clumped and had colonies characteristic of pheromone-induced cells at 32 degrees C but transferred plasmid DNA at a higher frequency only at the elevated temperature. The other three (pAM2708, pAM2709, and pAM2712) were derepressed at both temperatures for all three characteristics. Four of the mutations, including that of pAM2725, mapped within the traA determinant, whereas two mapped identically in a previously unnoted open reading frame (designated traD) putatively encoding a short (23-amino-acid) peptide downstream of the inhibitor peptide determinant iad and in the opposite orientation. One mutant could not be located in the regions sequenced. Studies showed that the traA and traD mutations could be complemented in trans with a DNA fragment carrying the corresponding regions"
Keywords:		"Amino Acid Sequence Bacterial Proteins/*genetics Base Sequence Cloning, Molecular *Conjugation, Genetic Cytotoxins/genetics Drug Resistance, Microbial Enterococcus faecalis/*genetics/growth & development *Escherichia coli Proteins *Gene Expression Regulat;"
Notes:		"Medlinede Freire Bastos, M C Tanimoto, K Clewell, D B eng GM33956/GM/NIGMS NIH HHS/ MO1-RR00042/RR/NCRR NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. 1997/05/01 J Bacteriol. 1997 May; 179(10):3250-9. doi: 10.1128/jb.179.10.3250-3259.1997"