title: Regulation of the Expression of De Novo Pyrimidine Biosynthesis Genes in Corynebacterium glutamicum.
abstract: Expression of pyrimidine de novo biosynthesis is downregulated by an exogenous uracil in many bacteria. In this study, we show that a putative binding motif sequence of PyrR is required for uracil-mediated repression of pyrR-lacZ translational fusion. However, the uracil response was still observed in the strain with the pyrR gene deleted, implying the existence of a uracil response factor other than PyrR which also acts through the PyrR binding loop region. Deletion of rho, encoding the transcription termination factor Rho, resulted in an increase in the expression of pyrR-lacZ. Moreover, the strain with a double deletion of pyrR and rho showed elimination of the uracil-responsive downregulation of the pyrR-lacZ. Therefore, expression of the pyrimidine biosynthetic gene cluster in Corynebacterium glutamicum is controlled by two different mechanisms mediated by PyrR and Rho.
  
  
  OBJECTIVE
  The pyr genes of C. glutamicum are downregulated in the presence of uracil in culture medium. The mRNA binding regulator PyrR represses the expression of pyr genes, as reported previously. However, the uracil response was still observed in the pyrR deletion strain. Deletion of rho in addition to pyrR deletion results in the elimination of the uracil response. Therefore, we identified the factors that are involved in the uracil response. Involvement of Rho in the regulation of pyrimidine de novo biosynthesis genes has not been reported.
authors.affiliation: Research Institute of Innovative Technology for the Earth, Kizugawa, Kyoto, Japan.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Research Institute of Innovative Technology for the Earth, Kizugawa, Kyoto, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Teramoto
authors.affiliation: Research Institute of Innovative Technology for the Earth, Kizugawa, Kyoto, Japan Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan mmg-lab@rite.or.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inui
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D010430:Pentosyltransferases / Q000235:genetics / Q000378:metabolism*; D011743:Pyrimidines / Q000096:biosynthesis*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D011743:Pyrimidines; D012097:Repressor Proteins; D010430:Pentosyltransferases; C098851:PyrR protein, bacteria