Question

You expressed a PA-GFP tagged-Actin in a cell. The incorporated PA-GFP-Actin in microfilaments was activated by illuminating the dotted box with UV light. You observed that the labeled Actin (in black lines) gradually moved toward cell center over time. Which of the following is TRUE?

1) The PA-GFP tagged-Actin was not activated by UV light
2) The labeled Actin moved away from the cell center over time
3) The labeled Actin remained stationary over time
4) The labeled Actin moved toward the cell center over time

Answer 1

The labeled Actin moved toward the cell center due to actin-myosin interactions, as observed in the cell after PA-GFP-Actin activation with UV light.

Step-by-step explanation:

The question pertains to observations made after expressing PA-GFP tagged-Actin within a cell and activating it with UV light in a specific region. Given that the labeled Actin gradually moved toward the center of the cell over time, the correct answer to the question is: the labeled Actin moved toward the cell center over time. This movement can be attributed to the actin-myosin interactions within the cellular cytoskeleton, particularly in processes like cytokinesis or cell motility.

In context, actin filaments often show movement towards the cell center as part of the cellular dynamics, which may involve predictable assembly and disassembly as well as interactions with myosin, contributing to contractile forces. The fluorescent tagging, like with the PA-GFP-Actin, allows researchers to observe these movements within cells in real time.