Research Interests

The plant cytoskeleton

All eukaryotic cells have cytoskeletons, which are made up of different classes of filamentous proteins that perform structural and other roles in the cell. One major component of the cytoskeleton is the microtubules. These are linear protein polymers that help to give cells their shape, act as tracks for transport of vesicles and organelles through the cell, and form the various arrays associated with mitosis and cytokinesis.

In plants, microtubules are thought to guide cell wall deposition during interphase. In rapidly elongating tissues, they are typically organised in parallel arrays, perpendicular to the axis of growth. This is thought to help restrict grown to one plane, so that the organs elongate, rather than expanding isotropically.

On entry into mitosis , the microtubules rearrange to form a narrow band around the middle of the cell, called the preprophase band. This band predicts the future site of cytokinesis, even though it disappears completely throughout mitosis. As mitosis begins, the preprophase band disassembles and the microtubules form the spindle , which captures the chromosomes and separates them to opposite sides of the cell. After karyokinesis is complete, microtubules assemble into a phragmoplast in the centre of the cell, depositing vesicles containing cell wall material and constructing a new cross-wall which joins up with the mother wall at precisely the spot predicted by the preprophase bad. Once cell division has finished, the characteristic interphase array returns.

I am interested in two main areas of plant cytoskeletal function and control:
1: How do cells co-ordinate their growth with their neighbours, and can cytoskeletal organisation be controlled over multiple cells?		2: How does the plant mitotic spindle form, and is it really that different from animal spindles?
	To answer this question, I have been working with an unusual arabidopsis mutant, rsw6, in which microtubules are well organised within cells, but disorganised with respect to neighbouring cells.		To answer this question, I have been working with an arabidopsis kinesin mutant, rsw7, which has massive spindle defects.