Research Summary
We are cell biologists devoted to advancing our knowledge of the cytoskeleton and intracellular motility in plant and fungal cells. Our ongoing investigations include the dynamics of microtubules and actin microfilaments during plant cell division and cell growth; Functions of kinesin motor proteins in mitosis and cytokinesis; Molecular mechanisms of cytoskeleton-mediated hyphal growth in filamentous fungi. Experiments are carried out in organisms like Arabidopsis thaliana, Oryza sativa (rice), and Gossypium hirsutum (cotton) which are used as reference systems for plant studies, and Aspergillus nidulans as a model for fungal studies.
A Picture from Our Experiments
This is an Arabidopsis cell undergoing cell division. Segregated sister chromatids are labeled in blue, microtubules in red, and the microtubule-associated protein MAP65-3 in green. Dr. Chin-Min Kimmy Ho devoted much of her dissertation to understanding the function of MAP65-3 in cytokinesis. The human counterpart of MAP65-3 is called PRC1 which also is required for cell division. Dr. Ho is tenured associate research fellow at Academia Sinica now. Research in her laboratory is devoted to understanding inter-organelle communication as well as symmetric and asymmetric cell divisions in flowering plants. Dr. Xingguang Deng moved the project one step forward by discovering a regulatory role of the mitotic kinase a-Aurora in the association of MAP65-3 with phragmoplast microtubules as shown in a recent paper. Currently, Ms. Man Kai Constance Tse is investigating genetic interactions and functional diversification among different MAP65 paralogous genes.
An Example of the Organisms We Are Working On
These are images of colonies of the filamentous fungus Aspergillus nidulans. This fungus is one of the model organisms used for classical genetic studies of fundamental biological processes like the cell cycle. The yellow color was given by the asexual conidial spores produced on the surface of the colonies. The images were taken from identical plates incubated at different temperatures indicated on the left. The strain to the left was a control one which demonstrated a typical growth phenomenon. The middle and right ones were mutants which had problems in nuclear migration. It has been demonstrated by many scientists that the mechanism for nuclear migration in this fungus is very similar to that regulating nuclear migration during fertilization and in brain development in mammals.