Limits...
Mechanochemical regulation of oscillatory follicle cell dynamics in the developing Drosophila egg chamber.

Koride S, He L, Xiong LP, Lan G, Montell DJ, Sun SX - Mol. Biol. Cell (2014)

Bottom Line: We propose that follicle cells in the epithelial layer contract against pressure in the expanding egg chamber.The activation process is cooperative, leading to a limit cycle in the myosin dynamics.The model demonstrates that in principle, mechanochemical interactions are sufficient to drive patterning and morphogenesis, independent of patterned gene expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218.

Show MeSH

Related in: MedlinePlus

Behavior of single follicle cells. (A) As we apply an increasing external stretching force to a single follicle cell, we see that (B) the follicle cell length increases with increasing force. However, as the force reaches a threshold, the cell starts to oscillate. At large forces the oscillations disappear and the cell continues to stretch. (C) The amount of activated Rho increases with increasing force, and there is an oscillation in the amount activated Rho. Rho reaches a maximum value at large force. (D–F) When the external force is held constant, three behaviors are seen. At low forces (D), the system settles to a steady level of activated Rho and MLC. At intermediate forces (E), the system exhibits an oscillatory limit cycle. At high forces (F), a steady state is again reached. Therefore our model predicts a Hopf bifurcation with increasing external force.
© Copyright Policy - creative-commons
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4230628&req=5

Figure 2: Behavior of single follicle cells. (A) As we apply an increasing external stretching force to a single follicle cell, we see that (B) the follicle cell length increases with increasing force. However, as the force reaches a threshold, the cell starts to oscillate. At large forces the oscillations disappear and the cell continues to stretch. (C) The amount of activated Rho increases with increasing force, and there is an oscillation in the amount activated Rho. Rho reaches a maximum value at large force. (D–F) When the external force is held constant, three behaviors are seen. At low forces (D), the system settles to a steady level of activated Rho and MLC. At intermediate forces (E), the system exhibits an oscillatory limit cycle. At high forces (F), a steady state is again reached. Therefore our model predicts a Hopf bifurcation with increasing external force.

Mentions: The simplest case is when a single follicle cell is under tension. This case is not possible to examine in experiments, but it is possible to explore using our model. Figure 2 shows an example in which an externally applied force stretches a single cell and the force gradually increases with time (Figure 2A). Our model predicts that the cell length will increase with increasing applied force (Figure 2B); however, activated Rho will also increase with increasing applied force (Figure 2C). The activated Rho catalyzes activation of myosin in the stress fibers, and the cellular contractile force increases to oppose the applied force. Within a range of applied force, the Rho-ROCK signaling network exhibits oscillations. This oscillation is a limit cycle (Figure 2E). The period of oscillation depends on the rate of Rho and ROCK activation. An analytical estimate of the oscillation period is given in the Supplemental Material (Supplemental Figures S4 and S5).


Mechanochemical regulation of oscillatory follicle cell dynamics in the developing Drosophila egg chamber.

Koride S, He L, Xiong LP, Lan G, Montell DJ, Sun SX - Mol. Biol. Cell (2014)

Behavior of single follicle cells. (A) As we apply an increasing external stretching force to a single follicle cell, we see that (B) the follicle cell length increases with increasing force. However, as the force reaches a threshold, the cell starts to oscillate. At large forces the oscillations disappear and the cell continues to stretch. (C) The amount of activated Rho increases with increasing force, and there is an oscillation in the amount activated Rho. Rho reaches a maximum value at large force. (D–F) When the external force is held constant, three behaviors are seen. At low forces (D), the system settles to a steady level of activated Rho and MLC. At intermediate forces (E), the system exhibits an oscillatory limit cycle. At high forces (F), a steady state is again reached. Therefore our model predicts a Hopf bifurcation with increasing external force.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4230628&req=5

Figure 2: Behavior of single follicle cells. (A) As we apply an increasing external stretching force to a single follicle cell, we see that (B) the follicle cell length increases with increasing force. However, as the force reaches a threshold, the cell starts to oscillate. At large forces the oscillations disappear and the cell continues to stretch. (C) The amount of activated Rho increases with increasing force, and there is an oscillation in the amount activated Rho. Rho reaches a maximum value at large force. (D–F) When the external force is held constant, three behaviors are seen. At low forces (D), the system settles to a steady level of activated Rho and MLC. At intermediate forces (E), the system exhibits an oscillatory limit cycle. At high forces (F), a steady state is again reached. Therefore our model predicts a Hopf bifurcation with increasing external force.
Mentions: The simplest case is when a single follicle cell is under tension. This case is not possible to examine in experiments, but it is possible to explore using our model. Figure 2 shows an example in which an externally applied force stretches a single cell and the force gradually increases with time (Figure 2A). Our model predicts that the cell length will increase with increasing applied force (Figure 2B); however, activated Rho will also increase with increasing applied force (Figure 2C). The activated Rho catalyzes activation of myosin in the stress fibers, and the cellular contractile force increases to oppose the applied force. Within a range of applied force, the Rho-ROCK signaling network exhibits oscillations. This oscillation is a limit cycle (Figure 2E). The period of oscillation depends on the rate of Rho and ROCK activation. An analytical estimate of the oscillation period is given in the Supplemental Material (Supplemental Figures S4 and S5).

Bottom Line: We propose that follicle cells in the epithelial layer contract against pressure in the expanding egg chamber.The activation process is cooperative, leading to a limit cycle in the myosin dynamics.The model demonstrates that in principle, mechanochemical interactions are sufficient to drive patterning and morphogenesis, independent of patterned gene expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218.

Show MeSH
Related in: MedlinePlus