Characterization of elongating T7 and SP6 RNA polymerases and their response to a roadblock generated by a site-specific DNA binding protein.


Journal Article

As a means of generating homogeneous populations of elongation complexes with the RNA polymerases encoded by phages T7 and SP6, transcription has been carried out in vitro on templates associated with the Gln-111 mutant of EcoRI endonuclease. The Gln-111 protein, as a result of a single amino acid substitution at position 111, lacks cleavage function yet shows higher than wild-type affinity for the EcoRI recognition sequence GAATTC. On a series of linear and circular templates associated with Gln-111 protein, blockage of the phage RNA polymerase elongation complex is observed. The 3' endpoint of the major blocked-length RNA species, just 3 bp upstream from the GAATTC, reveals an extremely close approach of polymerase's leading edge to essential contacts between Gln-111 protein and its binding site. In contrast to E. coli RNA polymerase, which is blocked stably and quantitatively by Gln-111 protein (Pavco, P.A. and Steege, D. A. (1990) J. Biol. Chem. 265, 9960-9969), the phage polymerases show substantial levels of readthrough transcription beyond the protein block.

Full Text

Cited Authors

  • Pavco, PA; Steege, DA

Published Date

  • September 11, 1991

Published In

Volume / Issue

  • 19 / 17

Start / End Page

  • 4639 - 4646

PubMed ID

  • 1891355

Pubmed Central ID

  • 1891355

International Standard Serial Number (ISSN)

  • 0305-1048

Digital Object Identifier (DOI)

  • 10.1093/nar/19.17.4639


  • eng

Conference Location

  • England