Disease relevance of pyrC

• Conformational heterogeneity in the Salmonella typhimurium pyrC and pyrD leader mRNAs produced in vivo [1].

High impact information on pyrC

• In accordance with predictions based on the nucleotide sequence, the results showed that the 5' end of pyrC and pyrD leader mRNA isolated from repressed cultures is folded into a secondary structure, whereas it is largely unstructured in mRNA isolated from derepressed cultures [2].
• The introduction of either a pyrA or pyrB mutation into a pyrC strain eliminated the observed growth inhibition [3].
• Additionally, a direct correlation was shown between the severity of growth inhibition of a pyrC auxotroph and the levels of the enzymes that synthesize carbamyl aspartate [3].
• The nicotinic acid phosphoribosyltransferase locus pncB was located on the Salmonella typhimurium linkage map counterclockwise relative to pyrC [4].
• Primer extension experiments on RNA from mutant strains that permit manipulation of the CTP and GTP pools showed that pyrC transcription may start at either a cytosine or a guanine residue, 2 bp apart [5].

Chemical compound and disease context of pyrC

• A cluster of genes essential for degradation of proline to glutamate (put) is located between the pyrC and pyrD loci at min 22 of the Salmonella chromosome [6].
• The pyrC gene of Salmonella typhimurium, encoding the third enzyme of pyrimidine nucleotide biosynthesis, dihydroorotase, has been cloned into the multicopy plasmid pBR322 [7].

Biological context of pyrC

• Growth of Salmonella typhimurium pyrC or pyrD auxotrophs was severely inhibited in media that caused derepressed pyr gene expression [3].
• A comparison of the polypeptides encoded by pyrC-complementing and non-complementing plasmids showed the gene product to have a molecular mass of approximately 37 kDa [7].
• S1 nuclease mapping indicated that transcription of pyrC is initiated 40 base pairs upstream from the translational start [7].
• Regulation of pyrC expression in Salmonella typhimurium: identification of a regulatory region [8].
• Four independently-isolated regulatory mutants, overexpressing pyrC, were found to have point mutations within the symmetry region and, significantly, the mutations occurred in sequences pertaining to either side of the stem of the putative hairpin of the transcript [8].

Associations of pyrC with chemical compounds

• (ii) The expression of pyrC and pyrD is regulated predominantly by a cytidine nucleotide [9].
• This requirement for arginine was completely suppressed by pyrB mutations and partially suppressed by pyrC and pyrD mutations [10].

Other interactions of pyrC

• The conformation of the leader regions of wild type pyrC and pyrD mRNA has been investigated by chemical and enzymatic probing of RNA isolated from cultures grown in repressing and derepressing conditions [2].
• Subcloning of a 184-base-pair DNA fragment, which included 118 base pairs upstream from the transcriptional start, and the first eight codons of the pyrC structural gene, into a galK expression vector, established that the pyrC promoter and regulatory region are harbored on this fragment [7].
• Isolation and characterization of pyrimidine mutants of Salmonella typhimurium altered in expression of pyrC, pyrD, and pyrE [11].

References