Dynamical modeling of microRNA action on the protein translation process

BMC Systems Biology

Table 2 Modeling of four mechanisms of microRNA action in the non-linear protein translation model

Observable value	Initiation(k₁)	Step after initiation(k₂)	Ribosome assembly (k₃)	Elongation (k₄)
Wild-type cap, inefficient initiation
Steady-state rate	slightly decreases	decreases	no change	decreases after threshold
Relaxation time	no change	no change	no change	goes up and down
Wild-type cap, efficient initiation
Steady-state rate	no change	slightly decreases after strong inhibition	no change	decreases
Relaxation time	no change	goes up and down	no change	no change
A-cap, inefficient initiation
Steady-state rate	decreases	decreases	no change	slightly decreases after strong inhibition
Relaxation time	no change	no change	no change	goes up and down
A-cap, efficient initiation
Steady-state rate	decreases after threshold	slightly decreases after strong inhibition	no change	decreases
Relaxation time	goes up and down	goes up and down	no change	increases

MicroRNA action effect is described for the protein synthesis steady rate and the relaxation time (see also Fig. 8). "Efficient initiation" and "inefficient initiation" correspond to two qualitatively different solution types of Nissan and Parker's model (see the beginning of "Effect of microRNA on the translation dynamics" section). The effect of A-cap structure is modeled by making the cap-dependent initiation step very slow (by making the k₁ parameter very small). It is assumed that the ribosome assembly step in protein translation, described by the k₃ rate constant, is not rate limiting.

ISSN: 1752-0509