Changing the plasmid design, from a cytomegalovirus (CMV) to an ubiquitin C (UbC) promoter substantially altered the duration of expression.
Two weeks later, mice were given water containing 0.05% of the tumour promoter, phenobarbital for the duration of experiments.
We interpret ΔT on as the net duration of promoter opening (T open ), abortive cycling (T abortive ), elongation from position +13 to position +60 (T elongation ), and the time for probe hybridization (T hybridization ).
The intercept of the plot with the time axis (l = 0) gives an estimate of the net time that RNAP spends on the DNA template without elongating, T stationary = 0.7 ± 0.3 s, which includes the net duration of promoter opening and abortive cycling (RPc, RPo and RPits), and, possibly, the time RNAP idles at the free DNA end before run-off.
In general, the binding of a repressor to the promoter significantly increases the duration of the closed complex formation, usually by reducing the probability that an RNAp will find the TSS (e.g. by blocking diffusion on the template) [ 7, 12].
Blue light pulses (473 nm, 5.2 mW mm−2) depolarized all fluorescently labelled neurons, yet the suprathreshold activation critically depended on the promoter used as well as the intensity and duration of light pulses.
Analyses delineated four ovarian cancer transcriptional subtypes, three microRNA subtypes, four promoter methylation subtypes and a transcriptional signature associated with survival duration, and shed new light on the impact that tumours with BRCA1/2 (BRCA1 or BRCA2) and CCNE1 aberrations have on survival.
A further modification, replacing the CMV promoter with a humanized one, has also conferred a significantly increased duration of expression.
By optimizing the dose and duration of aerosolized doxycycline exposure in mice possessing a ubiquitously expressed Rosa26 promoter-driven reverse tet-controlled transcriptional activator (rtTA) element, we induce transgene expression exclusively in the airways.
The short duration of transgene expression is likely related to the rapid silencing of the CMV promoter.
