Escherichia coli NusG protein stimulates transcription elongation rates in vivo and in vitro.

The rate of transcription elongation in Escherichia coli was reduced when cells were depleted of NusG. In a purified in vitro system, NusG accelerated the transcription elongation rate. The stimulation of the rate of transcription elongation by NusG appears to result from the suppression of specific transcription pause sites.

Two modes of transcription initiation in vitro at the rrnB P1 promoter of Escherichia coli.

The rrnB P1 promoter of Escherichia coli (starting sequence C-4-A-3-C-2-C-1-A+1-C+2-U+3-G+4) forms a binary complex with RNA polymerase that is highly unstable and requires the presence of transcription substrates ATP and CTP for stabilizing the enzyme-DNA association (Gourse, R. L. (1988) Nucleic Acids Res.

Transcript cleavage factors from E. coli.

Two transcription elongation factors (GreA and GreB) related in primary sequence were isolated from E. coli. Each factor induced cleavage of the nascent transcript in artificially halted elongation complexes followed by the loss of the 3' proximal fragment and resumption of elongation from the new 3' terminus.

Dominant lethal mutations near the 5' substrate binding site affect RNA polymerase propagation.

The segment Asp1064-Lys1073 in the beta subunit of Escherichia coli RNA polymerase is evolutionarily conserved and is located near the "5' face" of the nucleotide binding pocket as was shown by affinity labeling with priming substrates (Grachev, M. A., Lukhtamov, E.

Genetic dissection of the transcription cycle. A mutant RNA polymerase that cannot hold onto a promoter.

Deletion of 10 amino acids from a conserved motif in the beta subunit of Escherichia coli RNA polymerase (RNAP) leads to an interrupted transcription cycle and lethal phenotype. RNAP carrying the mutant subunit retains catalytic function and specificity of promoter recognition but is unable to efficiently hold onto DNA in the binary complex, resulting in a diminished initiation frequency. However, inefficient initiation by the mutant enzyme leads to processive and stable ternary elongating complex.