TY - JOUR
T1 - Dominant-negative mutants of prgX
T2 - Evidence for a role for PrgX dimerization in negative regulation of pheromone-inducible conjugation
AU - Bae, T.
AU - Dunny, G. M.
PY - 2001
Y1 - 2001
N2 - PrgX negatively regulates prgQ transcriptional read-through in the pheromone-inducible enterococcal conjugative plasmid pCF10. We isolated and characterized 13 dominant-negative prgX mutants, all of which mapped in either the N- or the C-terminus of PrgX. In all mutants, the in vivo level of Qa RNA, an antisense RNA to prgQ RNA, was greatly reduced. When oligomerization of PrgX was tested with a phage lambda cl repressor fusion system, the oligomerization domain was found to be between amino acid residues 78 and 280. When histidine-tagged PrgX (His-PrgX) was purified by nickel column chromatography from a strain also expressing PrgX, PrgX was co-purified with His-PrgX. Although PrgX was expressed at a much higher level than His-PrgX, an approximately equal amount of PrgX was co-purified. Pheromone induction greatly decreased the co-purification of PrgX. Based on these data, we propose that both the N- and the C-terminal domains of PrgX are required for PrgX positive autoregulation and for the repression of prgQ transcription read-through. In vivo, PrgX exists as a dimer, and dimerization is mediated by the central region of PrgX.
AB - PrgX negatively regulates prgQ transcriptional read-through in the pheromone-inducible enterococcal conjugative plasmid pCF10. We isolated and characterized 13 dominant-negative prgX mutants, all of which mapped in either the N- or the C-terminus of PrgX. In all mutants, the in vivo level of Qa RNA, an antisense RNA to prgQ RNA, was greatly reduced. When oligomerization of PrgX was tested with a phage lambda cl repressor fusion system, the oligomerization domain was found to be between amino acid residues 78 and 280. When histidine-tagged PrgX (His-PrgX) was purified by nickel column chromatography from a strain also expressing PrgX, PrgX was co-purified with His-PrgX. Although PrgX was expressed at a much higher level than His-PrgX, an approximately equal amount of PrgX was co-purified. Pheromone induction greatly decreased the co-purification of PrgX. Based on these data, we propose that both the N- and the C-terminal domains of PrgX are required for PrgX positive autoregulation and for the repression of prgQ transcription read-through. In vivo, PrgX exists as a dimer, and dimerization is mediated by the central region of PrgX.
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U2 - 10.1046/j.1365-2958.2001.02319.x
DO - 10.1046/j.1365-2958.2001.02319.x
M3 - Article
C2 - 11251846
AN - SCOPUS:0035109125
SN - 0950-382X
VL - 39
SP - 1307
EP - 1320
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 5
ER -