The role of RNA polymerase sigma subunit in promoter-independent initiation of transcription.
In bacteria, initiation of transcription depends on the RNA polymerase sigma subunit, which brings catalytically proficient RNA polymerase core to promoters by binding to specific DNA elements located upstream of the transcription start point. Here, we study sigma-dependent synthesis of a transcript that is used to prime replication of the single-stranded genome of bacteriophage M13. We show that, in this system, sigma plays no role in DNA recognition, which is accomplished solely through RNA polymerase core interaction with DNA downstream of the transcription start point. However, sigma is required for full-sized transcript synthesis by allowing RNA polymerase core to escape into productive elongation. RNA polymerase sigma may play a similar role during replication primer synthesis in other bacterial mobile elements whose life cycle involves a single-stranded DNA stage.
Zenkin
Nikolay
N
The Waksman Institute, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
Severinov
Konstantin
K
D001483:Base Sequence; D018983:DNA Footprinting; D004261:DNA Replication; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D003850:Deoxyribonuclease I; D007700:Kinetics; D008969:Molecular Sequence Data; D010957:Plasmids; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011994:Recombinant Proteins / Q000378:metabolism; D012808:Sigma Factor / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*
D011994:Recombinant Proteins; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D003850:Deoxyribonuclease I