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Results: 2

1.
Fig. 1.

Fig. 1. From: Evaluating the Drosophila Bicoid morphogen gradient system through dissecting the noise in transcriptional bursts.

Parameters affecting noise propagation. Activator input noise is converted to external noise (ηext) in target gene transcription based on Equation (10) in a simplified gene regulatory model. Here, ηext is shown as a function of ρi, the mean number of active copies. The effects of parameters that affect noise propagation are also shown. Such parameters include the activator noise strength (v), the activator threshold concentration (K) and the Hill coefficient (h). Figure 1A shows that ηext increases as the normalized noise strength (v/K) increases. Figure 1B shows that, at a given v/K, the effect of h on ηext is sensitive to ρ.

Feng He, et al. Bioinformatics. 2012 April 1;28(7):970-975.
2.
Fig. 2.

Fig. 2. From: Evaluating the Drosophila Bicoid morphogen gradient system through dissecting the noise in transcriptional bursts.

hb and otd have distinct noise properties in relation to the Bcd input noise. The experimentally measured ηtot (blue circles) in hb (A) and otd (C) intron dot numbers is dissected into ηext (green diamonds) and ηint (red squares) according to Equations (5) and (6), and the results are plotted against ρ. Solid lines are theoretical predictions based on Equation (10) in the simplified gene regulatory model. The adjusted R2-values of fitting the experimental data with the model for ηext, ηint and ηtot of hb are, respectively: 0.85, 0.99 and 1.00; the adjusted R2-values for ηext, ηint and ηtot of otd are, respectively: −0.48, 0.97 and 0.98. The negative R2 suggests that, constrained by the measured parameter values, the model cannot predict ηext of otd. Arrowheads show the boundary positions of ρ=ρmax/2. Here, K–values are measured as the mean Bcd concentrations at the marked boundary positions and h–values are extracted by fitting Equation (7) with the experimentally measured B–ρ profiles (He et al., 2011). Since fluctuations in Bcd concentration are dominated by Poisson-like molecular noise (He et al., 2010a), we perform a simple fitting of the experimentally measured Bcd noise to Poissonian distribution for extracting v-values. Figure 2B and D are scatter plots of dissected ηext (same as in Figures 2A and C but showing data only from the activation boundary regions for better data spread) against converted ηext (see text for details). Here, Figures 2B and C are for hb and otd, respectively. A linear regression line is also shown (with the equation in the inset box) for each panel.

Feng He, et al. Bioinformatics. 2012 April 1;28(7):970-975.

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