Figure 3
From: Mechanistic stochastic model of histone modification pattern formation
Performance of three histone modification spreading mechanisms. The rows show data for the (A) diffusion, (B) modification induced recruitment, and (C) combined diffusion and recruitment mechanisms. (A, B, C) Column i shows the model-predicted stationary histone modification patterns. The y-axis indicates the probability per nucleosome to be modified or occupied by a methyltransferase (Mt). Red: methylation mark, orange: methyltransferase, green: acetylation mark, and black: unmodified state. In the second column (labeled ii) the time to establish a stationary methylation state is evaluated. Simulations started from a condition in which all the nucleosomes are in the A state. The dark orange error bars contain 50% of the data points around the median and the light orange error bars show the minimal/maximal value regarding the number of methylated nucleosomes (binned/second). An example trace of a single simulation is shown in black. In the third column (iii) the probability distribution of the total transferase number and total modifications at steady state are displayed (same color coding as in column i). Column iv displays the relaxation dynamics. The error bars in column iv have the same meaning as in column ii. The simulations are initiated with all nucleosomes in the methylated state and occupied with methyltransferases, influx of new methyltransferase is not allowed at the initiation site. Parameters for all simulations are given in Table 1, with k on =2.4 s-1 and in (B, C) k recruitment =2.4 s-1.