RapA, a bacterial homolog of SWI2/SNF2, stimulates RNA polymerase recycling in transcription.
We report that RapA, an Escherichia coli RNA polymerase (RNAP)-associated homolog of SWI2/SNF2, is capable of dramatic activation of RNA synthesis. The RapA-mediated transcriptional activation in vitro depends on supercoiled DNA and high salt concentrations, a condition that is likely to render the DNA superhelix tightly compacted. Moreover, RapA activates transcription by stimulating RNAP recycling. Mutational analyses indicate that the ATPase activity of RapA is essential for its function as a transcriptional activator, and a rapA null mutant exhibits a growth defect on nutrient plates containing high salt concentrations in vivo. Thus, RapA acts as a general transcription factor and an integral component of the transcription machinery. The mode of action of RapA in remodeling posttranscription or posttermination complexes is discussed.
Sukhodolets
M V
MV
Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Cabrera
J E
JE
Zhi
H
H
Jin
D J
DJ
D000251:Adenosine Triphosphatases / Q000378:metabolism; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002843:Chromatin / Q000737:chemistry; D004265:DNA Helicases; D017931:DNA Primers / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D009687:Nuclear Proteins; D009690:Nucleic Acid Conformation; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification / Q000378:metabolism*; D010957:Plasmids; D012313:RNA / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D001426:Bacterial Proteins; D002843:Chromatin; D017931:DNA Primers; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C075519:rapA protein, Bacillus subtilis; D012313:RNA; D012321:DNA-Directed RNA Polymerases; D010749:Phosphoprotein Phosphatases; D000251:Adenosine Triphosphatases; D004265:DNA Helicases