Expression of Escherichia coli ribosomal protein and RNA polymerase genes cloned on plasmids

1979 ◽  
Vol 173 (1) ◽  
pp. 39-50 ◽  
Author(s):  
N. P. Fiil ◽  
D. Bendiak ◽  
J. Collins ◽  
J. D. Friesen
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Ribosomal Protein

The relationship between the spoT gene, the synthesis of stable RNA, ribosomal proteins, and the ββ′ subunits of RNA polymerase following a nutritional shiftup of Escherichia coli

1978 ◽  
Vol 56 (6) ◽  
pp. 528-533 ◽  
Author(s):  
Stephen M. Boyle ◽  
Frederick Chu ◽  
Nathan Brot ◽  
Bruce H. Sells
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Rna Synthesis ◽  
Transient Increase ◽  
Spot Gene ◽  
The Relationship

The level of ppGpp and rates of synthesis of stable RNA, ribosomal protein, and the β and β′ subunits of RNA polymerase were measured following a nutritional shiftup in Escherichia coli strains, NF 929 (spoT+) and NF 930 (spoT'−). In the spoT+ strain, ppGpp levels decreased 50% within 2 min following shiftup, and the rates of synthesis of stable RNA, ribosomal proteins, and the β and β′ subunits of RNA polymerase increased with little or no lag. In contrast, in the spoT− strain, ppGpp levels transiently increased 40% during the first 6 min following shiftup. An inhibition in the rate of stable RNA synthesis and a delay in the increased synthesis of ribosomal proteins and β and β′ subunits occurred concurrently with the transient increase in ppGpp. In addition, the DNA-dependent synthesis in vitro of the β and β′ subunits of RNA polymerase was inhibited by physiological levels of ppGpp. Because of the timing and magnitude of the changes in ppGpp levels in the spoT− strain versus the timing when the new rates of stable RNA, ribosomal protein, and β and β′ subunits synthesis are reached, it is concluded that ppGpp is not the sole element regulating the expression of these genes.

scholarly journals The Ribosomal Protein L2 Interacts with the RNA Polymerase α Subunit and Acts as a Transcription Modulator in Escherichia coli

2010 ◽  
Vol 192 (7) ◽  
pp. 1882-1889 ◽  
Author(s):  
Valentina Rippa ◽  
Claudia Cirulli ◽  
Benedetta Di Palo ◽  
Nunzianna Doti ◽  
Angela Amoresano ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Ribosomal Protein ◽  
Transcription Initiation ◽  
Direct Interaction ◽  
Regulation Of Transcription ◽  
Interacting Proteins ◽  
Α Subunit ◽  
Gene Reporter Assay ◽  
Ribosomal Protein L2

ABSTRACT Identification of interacting proteins in stable complexes is essential to understand the mechanisms that regulate cellular processes at the molecular level. Transcription initiation in prokaryotes requires coordinated protein-protein and protein-DNA interactions that often involve one or more transcription factors in addition to RNA polymerase (RNAP) subunits. The RNAP α subunit (RNAPα) is a key regulatory element in gene transcription and functions through direct interaction with other proteins to control all stages of this process. A clear description of the RNAPα protein partners should greatly increase our understanding of transcription modulation. A functional proteomics approach was employed to investigate protein components that specifically interact with RNAPα. A tagged form of Escherichia coli RNAPα was used as bait to determine the molecular partners of this subunit in a whole-cell extract. Among other interacting proteins, 50S ribosomal protein L2 (RPL2) was clearly identified by mass spectrometry. The direct interaction between RNAPα and RPL2 was confirmed both in vivo and in vitro by performing coimmunoprecipitation and bacterial two-hybrid experiments. The functional role of this interaction was also investigated in the presence of a ribosomal promoter by using a β-galactosidase gene reporter assay. The results clearly demonstrated that RPL2 was able to increase β-galactosidase expression only in the presence of a specific ribosomal promoter, whereas it was inactive when it was assayed with an unrelated promoter. Interestingly, other ribosomal proteins (L1, L3, L20, and L27) did not have any effect on rRNA expression. The findings reported here strongly suggest that in addition to its role in ribosome assembly the highly conserved RPL2 protein plays a specific and direct role in regulation of transcription.

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