Source:
Generated By: https://synbiohub.org/public/igem/igem2sbol/1
Created by: Shamik Mascharak, Justo Caballero and Sibel Sayiner
Date created: 2012-12-05 12:00:00
Date modified: 2015-05-08 01:14:06
Sequence for sigma 32 transcription factor
| Types | DnaRegion |
| Roles | Coding CDS |
| Sequences | BBa_M36888_sequence (Version 1) |
Description
The rpoH gene codes for sigma 32 (alternatively sigma H, RpoH) transcription factor, a component of RNA polymerase sigma 32 holoenzyme. This 32-kD stress factor belongs to the sigma-70 factor family and is involved in intracellular temperature regulation, initiating bacterial transcription of various chaperone proteins and proteases in response to sudden increases in ambient temperature. The gene is currently classified as essential, due to the fact that rpoH deletion mutants fail to grow at standard incubation temperatures.This part may be employed in heat shock-to-PoPs sensors by coupling expression of the rpoH gene to action of sigma 32-inducible promoters such as the htpG heat-shock promoter (part#: BBa_J45405). Transcriptional activation by rpoH transcripts is possible both within and without the sensor genetic circuit, as sigma factors can diffuse around the nucleus.
Notes
Designs incorporating this part into a feedback amplification loop must beware of likely rpoH-deletion mutants. This is due to overproduction of sigma 32 under leaky promoters such as htpG (BBa_J45405). Less deletion mutants in E. coli are noted when plasmids containing rpoH are cloned at higher temperature.Consider two facts before using this part. First, rpoH transcript activity is reduced under excess heat shock protein production. As such, feedback loops using rpoH should employ weaker bicistronic ribosome binding sites so as to optimize heat-shock response. Second, sigma 32 is turned over rapidly, with a half-life under 1 minute.