RegulonDB RegulonDB 10.7: Operon Form
   

pyrD operon and associated TUs in Escherichia coli K-12 genome




Operon      
Name: pyrD
This page displays every known transcription unit of this operon and their known regulation.


Transcription unit          
Name: pyrD
Synonym(s): OP00084
Gene(s): pyrD   Genome Browser M3D Gene expression COLOMBOS
Note(s): Based on genome-wide analysis, 472 single-gene knockouts were studied to determine their anaerobic fermentation products, based on the control of redox reactions. It was determined that the combined knockout of the guaB, pyrD, serA, fnr, arcA, and arcB genes enhanced D-lactate overproduction |CITS:[23563322]|.
Promoter
Name: pyrDp
+1: 1004732
Sigma Factor: Sigma70 Sigmulon
Distance from start of the gene: 36
Sequence: acgtttgcgttttttttgccgcaggtcaattcccttttggtccgaactcgcacataatacGcccccggtttgcacaccggg
                              -35                    -10    +1                   
Note(s): The transcriptional start site of this promoter can be switched among multiple start sites and this switching plays a very important role in the translational control of pyrC expression, because when the largest transcript is produced a secondary structure is formed that sequesters the Shine-Dalgarno sequence.
Evidence: [TIM]
Reference(s): [1] Larsen JN., et al., 1985
TF binding sites (TFBSs)
Type Transcription factor Function Promoter Binding Sites Growth Conditions Evidence (Confirmed, Strong, Weak) Reference(s)
LeftPos RightPos Central Rel-Pos Sequence
proximal Fis repressor pyrDp 1004721 1004735 -4.0 gtccgaactcGCACATAATACGCCCccggtttgca nd [AIBSCS], [GEA] [4]
Type Transcription factor Function Promoter Binding Sites Growth Conditions Evidence (Confirmed, Strong, Weak) Reference(s)
LeftPos RightPos Central Rel-Pos Sequence
proximal PurR-hypoxanthine1 repressor pyrDp 1004666 1004681 -58.5 gaaacaggttCGGAAAACGTTTGCGTtttttttgcc nd [AIBSCS], [APIORCISFBSCS], [BCE], [GEA] [2], [3]
Note(s): 1When the CTP level within the cell is high relative to the level of GTP, the pyrD gene is transcribed from a start site that allows formation of a secondary structure within the 5' end of the mRNA. This hairpin structure is thought to obscure the Shine-Dalgarno sequence, and it results in poor translation efficiency. When the CTP level is low relative to the level of GTP, pyrD is transcribed from an alternate start site. These shorter mRNAs are translated efficiently. The PurR protein, which represses the pyrD gene, is also regulated by the level of GTP, because this protein is active when GTP is present, but when PurR is active it repress the two genes, and when there is a high level of GTP these genes are translated efficiently. Thus, the two control systems can operate in opposition to one another.1When the CTP level within the cell is high relative to the level of GTP, the pyrD gene is transcribed from a start site that allows formation of a secondary structure within the 5' end of the mRNA. This hairpin structure is thought to obscure the Shine-Dalgarno sequence, and it results in poor translation efficiency. When the CTP level is low relative to the level of GTP, pyrD is transcribed from an alternate start site. These shorter mRNAs are translated efficiently. The PurR protein, which represses the pyrD gene, is also regulated by the level of GTP, because this protein is active when GTP is present, but when PurR is active it repress the two genes, and when there is a high level of GTP these genes are translated efficiently. Thus, the two control systems can operate in opposition to one another.





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