Regulation of heat acclimation by the omega subunit of RNA polymerase, group two sigma factor SigC and the Ssr1600 protein in Synechocystis
Vainio, Jesse (2021-11-26)
Regulation of heat acclimation by the omega subunit of RNA polymerase, group two sigma factor SigC and the Ssr1600 protein in Synechocystis
Vainio, Jesse
(26.11.2021)
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
suljettu
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe2021121460485
https://urn.fi/URN:NBN:fi-fe2021121460485
Tiivistelmä
The omega subunit of RNA polymerase is nonessential in several bacteria, including the cyanobacterium Synechocystis sp. PCC 6803. However, the omega-less ΔrpoZ strain has a heat lethal phenotype. Spontaneous suppressor mutations in the ssr1600 gene of the ΔrpoZ strain result in abnormally low amount of Ssr1600 protein, and the heat lethal phenotype of ΔrpoZ is rescued. Previous studies have suggested that Ssr1600 acts as an anti-σ factor antagonist for the group 2 σ factor SigC in high CO2. SigC is associated with stationary phase growth but is also required for the heat acclimation of Synechocystis. Growth experiments at 40 °C revealed that over-expression of the ssr1600 gene causes a heat sensitive phenotype in Synechocystis, indicating that excess Ssr1600 protein impairs heat acclimation of Synechocystis. The recruitment of SigC to RNAP was analyzed in Synechocystis-His, ΔrpoZ-His, ΔrpoZ-S1-His, ΔrpoZ-S2-His and ssr1600-oe-His strains at standard growth conditions and after 1- or 24-hours treatments at 40 °C. SigC was recruited by RNAP similarly in all strains at standard growth conditions or after 1 hour at 40 °C. However, after 24 hours at 40 °C the relative amount of RNAP-SigC holoenzyme was higher in the ssr1600-oe-His strain compared to the CS strain. To better understand the role of the Ssr1600 protein, a Δssr1600 strain, and strains containing non-phosphorylatable and phosphomimetic versions of the Ssr1600 protein will be constructed.